KPI visual not working properly

Hi all,

I have the following table:

I want to have the KPI visual do the following:

1) When all months (month name) are selected in the slicer, it should show the total revenue (category = revenue) based on the GL Amount
2) When one month is selected, it should show the total revenue of that month
3) When two or more months are selected, it should show the total revenue of these months

This works perfectly fine in a card visual, however the KPI visual keeps giving the total revenue of the last month in my dataset. Also, it does not add up revenue of multiple months when selected. 

Please help!!