diff --git a/message_private.admin.inc b/message_private.admin.inc
index b3778b8..631b326 100644
--- a/message_private.admin.inc
+++ b/message_private.admin.inc
@@ -8,69 +8,73 @@
  */
 function message_private_admin_settings() {
 
-  $form['message_private_email_notifications'] = array(
+  // Global email notifications on/off checkbox.
+  $form[MESSAGE_PRIVATE_EMAIL_NOTIFICATIONS] = array(
     '#type' => 'checkbox',
     '#title' => t('Message Private Email Notifications'),
-    '#default_value' => variable_get('message_private_email_notifications', TRUE),
+    '#default_value' => variable_get(MESSAGE_PRIVATE_EMAIL_NOTIFICATIONS, TRUE),
     '#description' => t('Global On / Off checkbox for emails notifying users of a new private message'),
   );
 
-  $form['message_private_message_limit'] = array(
+  // Role based message create limit on/off checkbox.
+  $form[MESSAGE_PRIVATE_MESSAGE_LIMIT] = array(
     '#type' => 'checkbox',
     '#title' => t('Limit Message Create By Role'),
-    '#default_value' => variable_get('message_private_message_limit', FALSE),
+    '#default_value' => variable_get(MESSAGE_PRIVATE_MESSAGE_LIMIT, FALSE),
     '#description' => t('Impose a message creation limit per interval. Users with multiple roles, get the highest limit from these roles'),
   );
 
-  $form['message_private_message_interval_limit'] = array(
+  // Conditional fieldset for all message limitation settings.
+  $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT] = array(
     '#title' => t('Message interval limits'),
     '#type' => 'fieldset',
     '#collapsible' => TRUE,
     '#collapsed' => TRUE,
     '#states' => array(
     'invisible' => array(
-      ':input[name="message_private_message_limit"]' => array('checked' => FALSE),
+      ':input[name="' . MESSAGE_PRIVATE_MESSAGE_LIMIT . '"]' => array('checked' => FALSE),
       ),
     ),
   );
 
   // Add a default fieldset.
-  $form['message_private_message_interval_limit'][MESSAGE_PRIVATE_DEFAULT_INDEX] = array(
+  $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT][MESSAGE_PRIVATE_DEFAULT_INDEX] = array(
     '#type' => 'fieldset',
     '#title' => 'Default limit',
     '#description' => t('Applies to all roles with blank entries below')
   );
 
-  $form['message_private_message_interval_limit'][MESSAGE_PRIVATE_DEFAULT_INDEX]['limit'] = array(
+  $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT][MESSAGE_PRIVATE_DEFAULT_INDEX][MESSAGE_PRIVATE_DEFAULT_LIMIT_NAME] = array(
     '#type' => 'textfield',
     '#title' => t('Limit'),
-    '#default_value' => variable_get('message_private_default_limit', TRUE),
+    '#default_value' => variable_get(MESSAGE_PRIVATE_DEFAULT_LIMIT_NAME),
     '#description' => t('Enter a message limit ' . MESSAGE_PRIVATE_MESSAGE_LIMIT_MIN . ' - ' . MESSAGE_PRIVATE_MESSAGE_LIMIT_MAX),
   );
 
-  $form['message_private_message_interval_limit'][MESSAGE_PRIVATE_DEFAULT_INDEX]['interval'] = array(
+  $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT][MESSAGE_PRIVATE_DEFAULT_INDEX][MESSAGE_PRIVATE_DEFAULT_INTERVAL_NAME] = array(
     '#type' => 'textfield',
     '#title' => t('Interval'),
-    '#default_value' => variable_get('message_private_default_interval', TRUE),
+    '#default_value' => variable_get(MESSAGE_PRIVATE_DEFAULT_INTERVAL_NAME),
     '#description' => t('Enter an interval in minutes ' . MESSAGE_PRIVATE_MESSAGE_INTERVAL_MIN . ' - ' . MESSAGE_PRIVATE_MESSAGE_INTERVAL_MAX),
   );
 
-  foreach(user_roles() as $id => $role) {
+  // Generate variable names for all roles used with get/set in admin form.
+  foreach (user_roles() as $id => $role) {
     $role_name = str_replace(' ', '_', $role);
     $limit_name = 'message_private_' . $role_name . '_limit';
     $interval_name = 'message_private_' . $role_name . '_interval';
 
-    $form['message_private_message_interval_limit'][$id] = array(
+    $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT][$id] = array(
       '#type' => 'fieldset',
       '#title' => $role,
     );
-    $form['message_private_message_interval_limit'][$id][$limit_name] = array(
+    $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT][$id][$limit_name] = array(
       '#type' => 'textfield',
       '#title' => t('Limit'),
       '#default_value' => variable_get($limit_name),
       '#description' => t('Enter a message limit ' . MESSAGE_PRIVATE_MESSAGE_LIMIT_MIN . ' - ' . MESSAGE_PRIVATE_MESSAGE_LIMIT_MAX),
     );
-    $form['message_private_message_interval_limit'][$id][$interval_name] = array(
+    $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT][$id][$interval_name] = array(
       '#type' => 'textfield',
       '#title' => t('Interval'),
       '#default_value' => variable_get($interval_name),
@@ -89,32 +93,59 @@ function message_private_admin_settings() {
  */
 function message_private_admin_settings_validate($form, &$form_state) {
 
+  // Validate the default fieldset values.
+  _message_private_validate_fieldset(
+    $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT][MESSAGE_PRIVATE_DEFAULT_INDEX][MESSAGE_PRIVATE_DEFAULT_LIMIT_NAME],
+    $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT][MESSAGE_PRIVATE_DEFAULT_INDEX][MESSAGE_PRIVATE_DEFAULT_INTERVAL_NAME],
+    $form_state['values'][MESSAGE_PRIVATE_DEFAULT_LIMIT_NAME],
+    $form_state['values'][MESSAGE_PRIVATE_DEFAULT_INTERVAL_NAME]
+  );
+
+  // Cycle through the settings for each role and validate.
   foreach (user_roles() as $id => $role) {
     $role_name = str_replace(' ', '_', $role);
     $limit_name = 'message_private_' . $role_name . '_limit';
     $interval_name = 'message_private_' . $role_name . '_interval';
 
-    // Check both textfields per fieldset are set, give error if only 1 is set.
-    if (isset($form_state['values'][$limit_name]) && isset($form_state['values'][$interval_name])) {
-      // Check is numeric and between the boundaries.
-      if (!ctype_digit($form_state['values'][$limit_name])
-        || $form_state['values'][$limit_name] > MESSAGE_PRIVATE_MESSAGE_LIMIT_MAX
-        || $form_state['values'][$limit_name] < MESSAGE_PRIVATE_MESSAGE_LIMIT_MIN) {
-        form_error($form['message_private_message_interval_limit'][$id][$limit_name],
-          t('Enter a numerical message limit between '
-            . MESSAGE_PRIVATE_MESSAGE_LIMIT_MIN . ' - ' . MESSAGE_PRIVATE_MESSAGE_LIMIT_MAX . '.'));
-      }
-      // Check is numeric and between the boundaries.
-      if (!ctype_digit($form_state['values'][$interval_name])
-        || $form_state['values'][$interval_name] > MESSAGE_PRIVATE_MESSAGE_INTERVAL_MAX
-        || $form_state['values'][$interval_name] < MESSAGE_PRIVATE_MESSAGE_INTERVAL_MIN) {
-        form_error($form['message_private_message_interval_limit'][$id][$interval_name],
-          t('Enter a numerical interval in minutes between '
-            . MESSAGE_PRIVATE_MESSAGE_INTERVAL_MIN . ' - ' . MESSAGE_PRIVATE_MESSAGE_INTERVAL_MAX . '.'));
-      }
-    } elseif (isset($form_state['values'][$limit_name]) || isset($form_state['values'][$interval_name])) {
-      form_error($form['message_private_message_interval_limit'][$id][$limit_name], t('Both a limit and interval value are required.'));
-      form_error($form['message_private_message_interval_limit'][$id][$interval_name]);
+    _message_private_validate_fieldset(
+      $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT][$id][$limit_name],
+      $form[MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT][$id][$interval_name],
+      $form_state['values'][$limit_name],
+      $form_state['values'][$interval_name]
+    );
+  }
+}
+
+/**
+ * Validate limit and interval values and show any errors on the form elements.
+ *
+ * @param $limit_element
+ *   Limit form element reference.
+ * @param $interval_element
+ *   Interval form element reference.
+ * @param $limit
+ *   Limit value to validate.
+ * @param $interval
+ *   Interval value to validate.
+ */
+function _message_private_validate_fieldset(&$limit_element, &$interval_element, $limit, $interval) {
+  // Validate role settings, check both textfields per fieldset are set.
+  if (!empty($limit) && !empty($interval)) {
+    // Check is numeric and between the boundaries.
+    if (!ctype_digit($limit) || $limit > MESSAGE_PRIVATE_MESSAGE_LIMIT_MAX || $limit < MESSAGE_PRIVATE_MESSAGE_LIMIT_MIN) {
+      form_error($limit_element,
+        t('Enter a numerical message limit between '
+          . MESSAGE_PRIVATE_MESSAGE_LIMIT_MIN . ' - ' . MESSAGE_PRIVATE_MESSAGE_LIMIT_MAX . '.'));
+    }
+    // Check is numeric and between the boundaries.
+    if (!ctype_digit($interval) || $interval > MESSAGE_PRIVATE_MESSAGE_INTERVAL_MAX || $interval < MESSAGE_PRIVATE_MESSAGE_INTERVAL_MIN) {
+      form_error($interval_element,
+        t('Enter a numerical interval in minutes between '
+          . MESSAGE_PRIVATE_MESSAGE_INTERVAL_MIN . ' - ' . MESSAGE_PRIVATE_MESSAGE_INTERVAL_MAX . '.'));
     }
+  } elseif (!empty($limit) || !empty($interval)) {
+    // Show error if only 1 textfield is set in each fieldset.
+    form_error($limit_element, t('Both a limit and interval value are required.'));
+    form_error($interval_element);
   }
 }
diff --git a/message_private.module b/message_private.module
index 82271bb..b04b1f3 100755
--- a/message_private.module
+++ b/message_private.module
@@ -3,6 +3,31 @@
  * Message Private with access permissions based on message fields.
  */
 
+/**
+ * The variable name for email notifications.
+ */
+define('MESSAGE_PRIVATE_EMAIL_NOTIFICATIONS', 'message_private_email_notifications');
+
+/**
+ * The string name for message limit.
+ */
+define('MESSAGE_PRIVATE_MESSAGE_LIMIT', 'message_private_message_limit');
+
+/**
+ * The string name for message interval limit.
+ */
+define('MESSAGE_PRIVATE_MESSAGE_INTERVAL_LIMIT', 'message_private_message_interval_limit');
+
+/**
+ * The variable name to be used when fetching default limit.
+ */
+define('MESSAGE_PRIVATE_DEFAULT_LIMIT_NAME', 'message_private_default_limit');
+
+/**
+ * The variable name to be used when fetching default interval.
+ */
+define('MESSAGE_PRIVATE_DEFAULT_INTERVAL_NAME', 'message_private_default_interval');
+
 /**
  * The default index for settings such as role.
  */
@@ -28,6 +53,7 @@ define('MESSAGE_PRIVATE_MESSAGE_INTERVAL_MAX', 1440);
  */
 define('MESSAGE_PRIVATE_MESSAGE_INTERVAL_MIN', 1);
 
+
 /**
  * Implements hook_help().
  */
@@ -247,26 +273,36 @@ function message_private_form_message_ui_instance_message_manage_alter(&$form, &
  *   The form state including values submitted.
  */
 function message_private_form_message_ui_instance_message_manage_validate($form, &$form_state) {
-  // If there is an imposed message limit, set in the admin settings interface.
-  if (variable_get('message_private_message_limit', FALSE)) {
+  // If there is an imposed message limit set in the admin settings interface.
+  if (variable_get('message_private_message_limit', FALSE)
+    && !user_access('bypass private message access control')) {
     global $user;
+
+    // Get the role belonging to user with max message limit.
     $rid = _message_private_max_message_limit_role($user->roles);
     $role = user_role_load($rid);
-    $limit_name = 'message_private_' . $role->name . '_limit';
-    $interval_name = 'message_private_' . $role->name . '_interval';
+
+    // Get the message limitation settings for this role.
+    $role_name = str_replace(' ', '_', $role->name);
+    $limit_name = 'message_private_' . $role_name . '_limit';
+    $interval_name = 'message_private_' . $role_name . '_interval';
     $interval = variable_get($interval_name);
     $limit = variable_get($limit_name);
-    // Get total amount of messages since last interval.
+
+    // Calculate timestamp of the last interval.
     $current_timestamp = time();
     $interval_timestamp = strtotime('-' . $interval . ' minutes', $current_timestamp);
+
+    // Get total amount of this user's messages since last interval.
     $query = new EntityFieldQuery();
     $total = $query->entityCondition('entity_type', 'message')
       ->entityCondition('bundle', 'private_message')
-      ->propertyCondition('created', $interval_timestamp, '>')
+      ->propertyCondition('timestamp', $interval_timestamp, '>')
       ->propertyCondition('uid', $user->uid)
       ->count()
       ->execute();
-    // if total < limit, send message, if not display error.
+
+    // Display error preventing message create when total messages over limit.
     if($total >= $limit) {
       form_error($form, t('Message create limit reached. Please try again later.'));
     }
@@ -338,10 +374,12 @@ function message_private_form_user_profile_form_alter(&$form, &$form_state, $for
  */
 function _message_private_max_message_limit_role($roles) {
   $limits = array();
-  // Get the default limit and interval.
-  $limit_name = 'message_private_default_limit';
-  $interval_name = 'message_private_default_interval';
-  $limits[MESSAGE_PRIVATE_DEFAULT_INDEX] = variable_get($interval_name) / variable_get($limit_name);
+  $limit = variable_get(MESSAGE_PRIVATE_DEFAULT_LIMIT_NAME);
+  $interval = variable_get(MESSAGE_PRIVATE_DEFAULT_INTERVAL_NAME);
+  // Ensure we have existing valid numerical values for both variables.
+  if (!empty($limit) && ctype_digit($limit) && !empty($interval) && ctype_digit($interval)) {
+    $limits[MESSAGE_PRIVATE_DEFAULT_INDEX] = $interval / $limit;
+  }
 
   // Cycle through the roles and get each limit and interval.
   foreach ($roles as $rid => $role) {
@@ -351,10 +389,11 @@ function _message_private_max_message_limit_role($roles) {
     $interval = variable_get($interval_name);
     $limit = variable_get($limit_name);
 
-    // Ensure values are greater than 0 & get interval required for one message.
-    if ($interval >= MESSAGE_PRIVATE_MESSAGE_INTERVAL_MIN && $limit >= MESSAGE_PRIVATE_MESSAGE_LIMIT_MIN) {
-      $limits[$rid] = $interval_name / $limit;
+    // Ensure we have existing valid numerical values for both variables.
+    if (!empty($limit) && ctype_digit($limit) && !empty($interval) && ctype_digit($interval)) {
+      $limits[$rid] = $interval / $limit;
     }
   }
+  // The min value corresponds to the lowest interval required per message.
   return array_search(min($limits), $limits);
 }