WTD running total based on DIVIDE

Hello everyone!

I have a measure that shows me the daily budget level based on a weekly target:

Sales Phasing = DIVIDE([Budget], [# Working Days per Week])

[Budget] is a column based on a year-week granularity.

To get the daily target I divide the budget by the number of working day per week.

Now I would like to accumulate this daily budget by month.

Something like:

How would you do that?

I guess a simple running total will not work based on the result of a DIVID function, right?

This is my MTD measure for the actual sales:

Sales MTD = 
CALCULATE (
    [Sales],
    FILTER (
        ALL ( 'Calendar' ),
        'Calendar'[Fiscal Year]
            = MAX ( 'Calendar'[Year] )
            && 'Calendar'[Date]
                <= MAX ( 'Calendar'[Date] )
            && 'Calendar'[Fiscal Month Number]
                = MAX ( 'Calendar'[Fiscal Month Number] )
    )
)