Not able to understand this logic.

[Rajveer]

=Sum({$<PAID={1,2},FISCAL_MONTH=,FISCAL_YEAR=,QTR_NAME=,
PARENT_FISCAL_MONTH={">=$(=date(addmonths(max({<PAID={1,2}>}Date#(PARENT_FISCAL_MONTH,'YYYYMM')),-12),'YYYYMM'))
<=$(=date(max({<PAID={1,2}>}Date#(PARENT_FISCAL_MONTH,'YYYYMM')),'YYYYMM'))"} >}DISCOUNT_TAKEN_USD_AMOUNT)

[vincent_ardiet_]

This is computing the sum of DISCOUNT_TAKEN_USD_AMOUNT in the following context:
 - PAID values are 1 and 2
 - Selections on FISCAL_MONTH, FISCAL_YEAR and QTR_NAME are not took in account
 - PARENT_FISCAL_MONTH is greater or equal to 12 months before the max PARENT_FISCAL_MONTH (for value with PAID = 1 and 2)
 - PARENT_FISCAL_MONTH is lower or equal to the max PARENT_FISCAL_MONTH (for value with PAID = 1 and 2)

[Rajveer]

Thank you @vincent_ardiet_