Hi Emma,
If you look in detail into SAPGetData and SAPSetData you can see that ...Set... has one more parameter than ...Get.... That's why shift in that place.
Yes, this is measure name (in both formulas), but same measure is represented by a GUID. You can get it from Query definition or from SAPGetData. I suggested the later because it's easier to find.
And that's how it works in our case.
-Gersh