I'm trying to implement a writeback measure group for required quantities by month and part number. I'm puzzled by the behavior I am seeing in Excel 2013, but I don't know if SSAS or Excel is responsible.
If the dimension selection in Excel is not the native granularity of the the underlying Measure Group, 'Publishing' the data distributes the data as equally as it can among the dimension members. Which is not necessarily wrong, but a bit weird and definitely unexpected. e.g.
If I publish a value at the year level, it will divide it equally into quarters and months.
If I don't include the part dimension it will divide the quantity equally into all part numbers.
I need to prevent data from being published anywhere but at the intersection of Part and Month. My only thought so far is to control write access through the Role with an expression that includes the Measure and Dimensions, but I'm not having much luck with that due to my limited MDX skills. Is there any other mechanism to modify writeback behavior?