if(Index(concat([Fiscal Month],','),'Jul') >= 1,
This will find there the selected [Fiscal Month] is having Jul or not...
If it is July, the Index will find out the Index of the July which would greater than or equal to 1....
in case of July is true
Sum({$<[Fiscal Year] = {$(=max([Fiscal Year]))}, [Fiscal Month] = {'Jul'}>} [Ledger Amount])
You will get SUM([Ledger Amount] where Fiscal Year = Max Fiscal Year and Fiscal Month = Jul
ortherwise
Sum({$<[Fiscal Year] = {$(=max([Fiscal Year]))}, [Fiscal Month] = {'Jul'}>}[Forecast Amount]))
You will get SUM([Forecast Amount] where Fiscal Year = Max Fiscal Year and Fiscal Month = Jul
