diff --git a/src/model/core/operational_reserves.jl b/src/model/core/operational_reserves.jl
index 54d6dab07..d5d0df936 100644
--- a/src/model/core/operational_reserves.jl
+++ b/src/model/core/operational_reserves.jl
@@ -270,7 +270,8 @@ function operational_reserves_core!(EP::Model, inputs::Dict, setup::Dict)
     # N-1 contingency requirement is considered only if Unit Commitment is being modeled
     if UCommit >= 1 &&
        (inputs["pDynamic_Contingency"] >= 1 || inputs["pStatic_Contingency"] > 0)
-        add_to_expression!(EP[:eRsvReq], EP[:eContingencyReq])
+        # EP[:eRsvReq] = EP[:eRsvReq] + EP[:eContingencyReq]
+        add_similar_to_expression!(EP[:eRsvReq], EP[:eContingencyReq])
     end
 
     ## Objective Function Expressions ##
diff --git a/src/model/expression_manipulation.jl b/src/model/expression_manipulation.jl
index 33b0b8e8e..92b1daac2 100644
--- a/src/model/expression_manipulation.jl
+++ b/src/model/expression_manipulation.jl
@@ -138,6 +138,14 @@ function add_similar_to_expression!(expr1::AbstractArray{GenericAffExpr{C, T}, d
     return nothing
 end
 
+# If the expressions are vectors of numbers, use the += operator
+function add_similar_to_expression!(arr1::AbstractArray{T, dims}, arr2::AbstractArray{T, dims}) where {T <: Number, dims}
+    for i in eachindex(arr1)
+        arr1[i] += arr2[i]
+    end
+    return nothing
+end
+
 ###### ###### ###### ###### ###### ######
 # Element-wise addition of one term into an expression
 # Both arrays must have the same dimensions
diff --git a/test/expression_manipulation_test.jl b/test/expression_manipulation_test.jl
index 71891d80a..8aae64c39 100644
--- a/test/expression_manipulation_test.jl
+++ b/test/expression_manipulation_test.jl
@@ -92,6 +92,12 @@ let
     GenX.add_similar_to_expression!(EP[:large_expr], EP[:large_const_expr])
     @test all(EP[:large_expr][:] .== 18.0)
 
+    # Test add_similar_to_expression! with AbstractArray{Number}
+    @expression(EP, eArr1[i = 1:100, j = 1:50], i*10.0+j*10.0)
+    @expression(EP, eArr2[i = 1:100, j = 1:50], -(i*10.0+j*10.0))
+    GenX.add_similar_to_expression!(EP[:eArr1], EP[:eArr2])
+    @test all(EP[:eArr1][:] .== 0.0)
+
     # Test add_similar_to_expression! returns an error if the dimensions don't match
     GenX.create_empty_expression!(EP, :small_expr, (2, 3))
     @test_throws ErrorException GenX.add_similar_to_expression!(EP[:large_expr],