Weighted Average Power BI

I am trying to get a weighted average for an absolute % error.  Weighting is on units sold (product quantity) per item (item ID).  I am able to get correct answers at a "branch plant" (AU01, EU01, SU01) but can not seem to get the correct answer at the category level (Paper, Kits).  

Here is the formula I am using (I am new to DAX so this is the autogenerated "quick measure" that Power BI create).  

Weighted Absolute % Error =

DIVIDE(

    SUMX(

        KEEPFILTERS(VALUES('Item Attributes'[Item ID])),

        CALCULATE([Absolute Error %] * [Product Quantity])

    ),

    SUMX(

        KEEPFILTERS(VALUES('Item Attributes'[Item ID])),

        CALCULATE([Product Quantity])

    )

)

 

Using a matrix table if I use category as a subset of warehouse the numbers are accurate. 

 

But if I flip the category and market, the category numbers are incorrect, but the warehouse numbers are correct.  

 

 

What do I need to change in order to have the category numbers apprear correclty? 

 

Thank you for your help.