Prior 3 month Set Analysis and Above function

[john_Talampas]

Hello,

I used the following logic to try to develop a table to show, by YYYY-MM, the total Amount and the Prior 3 month Amount.  It looked promising until I realized it would not show the first 3 months (due to my selection of fiscal year 2019). 

Prior 3 month

=If(Sum(DENIAL_AMOUNT_LINE) > 0, Above(sum({<CalendarYearMonth=>}[DENIAL_AMOUNT_LINE]),3))

I've gone back to the drawing board and am trying to use set analysis to get the prior 3 month amount.  I'm currently using the following logic in the table below (Prior 3 months TESTING):

=sum({<CREATE_DATE= {">=$(=AddMonths(CREATE_DATE),-3)<=$(=AddMonths(CREATE_DATE),-3)"} >} DENIAL_AMOUNT_LINE)

However I am doing something incorrectly as my numbers are matching back to the "Amount" column.  Ideally I'd like to show what the prior 3 month amount was.

Can someone point me in the right direction?  Any help is appreciated. 

John