Dynamically calculate sum for current and historical data

Hi,

I am trying to develop a measure that returns the amount of money held in unresolved files. The metric needs to show the values at any point in time, and not just the live data. To facilitate that, we have merged a live data and cutoff data report in our fact table. 

The measure looks something like this 

$ Debt = 
VAR Live = CALCULATE (SUMX(FILTER(Fact table, report = "Live" && {conditions}), debt_amt)), userelationship(timestamp, date))

Var Historical = CALCULATE (SUMX(FILTER(Fact table, report = "Historical" && {conditions}), debt_amt)),userelationship(timestamp, date))

RETURN 

IF (YEAR(Max(Dim_Date[Date])) = YEAR(TODAY) && MONTH(MAX(Dim_Date[Date])) = MONTH(TODAY), Live, Historical)

The measure works as intended when viewing month by month, but the problem arises when trying to view it over different time dimensions i.e quarterly/half yearly basis - where it sums up the debt over the time period and returns a total value. 

However, I would like the measure to return the value at the last point in time if selected over a larger time period (i.e. if selected over a quarter, it should show the debt value at the last date in that quarter, and not add up the 3 months). 

Any tips and suggestions would be greatly appreciated. 

Thanks