Non calculated dimensions ignoring selection

[eli_K12]

Hello. 

I am trying to have the dimension Purchase requester ignore all those fields when selected. They are irrelevant and when I select one of them it is causing null data because i know it is there. This is not a calculated field. Does anyone see anything wrong with this or if this is the effective strategy for what I am trying to do. Any assistance would be greatly appreciated. 

=Aggr(Only({<[Month]=, [Year]= ,QTR= ,[Month Num]= ,[Month -Short-]= ,Month= ,[GL Period]= ,[CC]= ,[GL Act]= , [PO Creation Date] = {"=Year(Only({1}[PO Creation Date])) >= $(v3PrevYear)"}>}[Purchase Requester]),[Purchase Requester])

Thank You