Divide column values every week

Hi, harmonvi 

Based on your description, I created data to reproduce your scenario. The pbix file is attached in the end.

Productivity:

Hours:

Then you need to make the week columns selected and unpivot them in Power Query.

Then you may create a measure as below.

Result = 
DIVIDE(
    DIVIDE(
        SUM(Hours[Value]),
        CALCULATE(
            SUM(Productivity[Value]),
            FILTER(
                ALL(Productivity),
                [Name] in DISTINCT(Hours[Name])&&
                [Week] in DISTINCT(Hours[Week])
            )
        ),0
    ),8
)

Result:

Best Regards

Allan

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