Power Pivot DAX Monthly average

Hi,

I've got the reuslt I want, which is a monthly average but I'm not sure if there's a better way, first I'm getting the avarage using ;

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And then Calculate ;

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Is there a better or alternate way of doing this, also I did try using variables but that didn't work I'm preusuming due to not being affected by the calculation filters.

Example attached.

Richard.