Column total incorrect for converted amounts

[SUNNY ISLAND]

I have the following dax formula to convert values from various currencies to SGD. The total column does not add up. Instead of showing $16.5m, it is showing $25.2m. The converted amount on each row is correct but not the total for the column.

As I'm fairly new to DAX, appreciate assistance on how to get the following DAX formula working. A copy of my model is attached below.
-----
Total value in SGD =
VAR
_CURRENCY = MAX(Data[Report curr])
VAR
_CONVERSIONRATE =
calculate(max('Exch rate'[Exch rate]), 'Exch rate'[Report Curr] = _CURRENCY)
RETURN
sumx(data,_CONVERSIONRATE*(Data[Value]))
----

 

[RoryA]

Your grand total is not simply a sum of the values above it, it uses the same measure as every other row. So you're getting one conversion rate - for whatever MAX(Data[Report curr]) returns - applied to the total of Data[Value]. See Alberto's article here: Summing values for the total - SQLBI