YTD calculation

[Anonymous]

i have the following code to calculate amount

=IF( ValueLoop(1,12,1)=1 ,num(sum({$<Network={1},Src={1},BillMonthNo={'<=$(vBillMonthNo)'} >}Amount),'R # ##0,00')....

this code works wneh nothing on BillMonth is selected therefore vBillMonthNo=12 so everything is calculated

but wen i select a month say Nov my vBillMonthNo becomes 11 but now it only calculates for one month

please assit