DAX to Calculate Same Week Prior Year

[DataSundowner]

Hi Everyone. I'm trying to calculate what sales were for each week prior year. I have created a measure looks like below. It works fine to calcualte for each week. However, it stops calculating the total when the date range corsses more than one year. How can I fix this? Thanks in advance. 

Amt Prior Yr = 
IF (
    HASONEVALUE ( DimDate[ISO_Year] ),
    CALCULATE (
        SUM(SalesFact[Amt]),
        FILTER (
            ALL ( DimDate ),
            DimDate[ISO_Year] = VALUES ( DimDate[ISO_Year] ) - 1
                && CONTAINS(
                    VALUES ( DimDate[ISO_WeekNum] ),
                     DimDate[ISO_WeekNum],
                     DimDate[ISO_WeekNum] )
        )
    ),
    BLANK()
)

Total line works fine if in the same year:

Total line stops working when there are multiple years:

[Greg_Deckler · Accepted solution]

@DataSundowner First, please vote for this idea: https://ideas.powerbi.com/ideas/idea/?ideaid=082203f1-594f-4ba7-ac87-bb91096c742e

This looks like a measure totals problem. Very common. See my post about it here: https://community.powerbi.com/t5/DAX-Commands-and-Tips/Dealing-with-Measure-Totals/td-p/63376

Also, this Quick Measure, Measure Totals, The Final Word should get you what you need:
https://community.powerbi.com/t5/Quick-Measures-Gallery/Measure-Totals-The-Final-Word/m-p/547907

Also: https://youtu.be/uXRriTN0cfY
And: https://youtu.be/n4TYhF2ARe8

[DataSundowner]

Hi @Greg_Deckler Thank you for your quick reply. That The Final Word post did solved my issue. Thanks!