Why are OriginRef and DestinationRef not the same type?

[skinkie]

No description provided.

[haeckerbaer]

Some more information:
in siri_journey_support.xsd we have <xsd:element name="OriginRef" type="JourneyPlaceRefStructure"> and <xsd:element name="DestinationRef" type="DestinationRefStructure"> as the "base" types.

However, within the DatedVehicleJourneyIndirectRefStructure, introduced in SIRI v2.1, we have yet another definition as both Origin and DestinationRef are of type StopPointRefStructure.

Very confusing indeed but at least all these types point to NMTOKEN eventually:
`<xsd:complexType name="JourneyPlaceRefStructure">
xsd:annotation
xsd:documentationReference to a PLACE visited by a VEHICLE JOURNEY.</xsd:documentation>
</xsd:annotation>
xsd:simpleContent
<xsd:extension base="xsd:NMTOKEN"/>
</xsd:simpleContent>
</xsd:complexType>

<xsd:complexType name="DestinationRefStructure">
xsd:annotation
xsd:documentationType for reference to a DESTINATION.</xsd:documentation>
</xsd:annotation>
xsd:simpleContent
<xsd:extension base="DestinationCodeType"/>
</xsd:simpleContent>
</xsd:complexType>

<xsd:simpleType name="DestinationCodeType">
xsd:annotation
xsd:documentationType for identifier of a DESTINATION.</xsd:documentation>
</xsd:annotation>
<xsd:restriction base="xsd:NMTOKEN"/>
</xsd:simpleType>

<xsd:simpleType name="StopPointCodeType">
xsd:annotation
xsd:documentationType for identifier of a SCHEDULED STOP POINT.</xsd:documentation>
</xsd:annotation>
<xsd:restriction base="xsd:NMTOKEN"/>
</xsd:simpleType>`

@skinkie Should we harmonize these types and reference StopPointRefStructure eveywhere?