Custom Rollup Without a Hierarchy

We had a scenario where the user want to see average at the ROW level and the SUM of the averages at the TOTAL level in a matrix. There was no hierarchy on the rows. The rows have the 'Financial Summary Line Type'[Digital Description] column.

Here's the brute force solution:

LineType gets the value of  the 'Financial Summary Line Type'[Digital Description] column for the DETAIL rows and BLANK() for the TOTAL row.

Average Sales (Digital Rollup) =

VAR LineType = SELECTEDVALUE('Financial Summary Line Type'[Digital Description], BLANK())

VAR AllDigitalLineTypes =

ADDCOLUMNS(

CALCULATETABLE(

VALUES('Financial Summary Line Type'[Digital Description]),

'Financial Summary Line Type'[Digital] = 1

),

"@AverageSales", CALCULATE(DIVIDE(SUM('Financial Summary'[TransactionAmount]), COUNTROWS('Calendar')))

)

RETURN

IF (

NOT ISBLANK(LineType),

DIVIDE(SUM('Financial Summary'[TransactionAmount]), COUNTROWS('Calendar')),

SUMX(AllDigitalLineTypes, [@AverageSales])

)