DAX measure to switch between 2 measures based on cell value

[DBA1138]

Hello,

I have balances in 2 currencies; CAD and USD. 
I want to convert USD to CAD and achieve the expected result below.

Currency	Total Closing Balance	Current conversion applied to closing	Expected Result
USD	$34,490,504.28	$42,488,852.22	$42,488,852.22
CAD	-$26,645,252.30	-$32,824,286.31	-$26,645,252.30

Total Closing Balance = SUM('Cash Balances'[Closing Balance])

Current conversion applied to closing =

[Total Closing Balance] * SUM('Current Day Exchange Rate'[Current Exchange Rate])

How would I go about this? I've tried using IF() in a calculated column, but I run into a circular dependency error as I already have a another calculated column (ideally, I'll use a measure for that as well). If I try using IF() as a measure instead, I get the following:

I tried making the IF() function work by creating a conditional column in Power Query, then creating the following measure:

Measure =

IF(

SUM('Cash Balances'[True/False (currency conversion)]) > 0,

[Current conversion applied to closing],

[Total Closing Balance]

)

The row values are right in the table visual, but the totals are wrong:

What am I missing? 

[Greg_Deckler]

@DBA1138 - In measures, you need to wrap your column references in an aggregator like MAX, MIN, etc.