SecondaryMeasureType for psets P_REFERENCEVALUE properties?

Maybe I'm missing something but what I've noticed that in [IFC4_ADD2.ifc](https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/annex/annex-a/general-usage/IFC4_ADD2.ifc) (library of pset templates for IFC4) for some `P_REFERENCEVALUE` properties there is also defined `SecondaryMeasureType`.

For example, property `MeasuredPressureDrop` (part of `Pset_ValvePHistory`) in .ifc has both primary (`IfcTimeSeries`) and secondary (`IfcPressureMeasure`) measure type:

```
#19808= IFCSIMPLEPROPERTYTEMPLATE('0AoSO0qXGHuO00025QrE$V',$,'MeasuredPressureDrop','The actual pressure drop in the fluid measured across the valve.',.P_REFERENCEVALUE.,'IfcTimeSeries','IfcPressureMeasure',$,$,$,$,.READWRITE.);
```

But in [.xml for that pset](https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/psd/Pset_ValvePHistory.xml) secondary measure `IfcPressureMeasure` doesn't seem to be mentioned anywhere. And it's also cannot be found in similar .xml for the IFC4X3 (attached it's code below for reference).

Is there some other way I can check if reference property has secondary measure type and what it is?

```xml

Pset_ValvePHistory
Valve performance history common attributes of a typical 2 port pattern type valve.


IfcValve

IfcValve


PercentageOpen
The ratio between the amount that the valve is open to the full open position of the valve.





MeasuredFlowRate
The rate of flow of a fluid measured across the valve.





MeasuredPressureDrop
The actual pressure drop in the fluid measured across the valve.

```