weighted avg and aggr

[coloful_architect]

Hi guys,

I have a table with competitors and own company's sales units as well as prices.

Trying to use aggar function to calculate the competitors 's sales units.

as you see at the screenshot, for some reason , I fail to get expected number. aggar return me null

what I am using is 

Sum({<Supplier={'competitor'},Month = {"$(=Max({1}Month))"}>} [QTY Each])

*
(aggr(avg({<Month = {"$(=Max(Month))"},[Supplier]=-{'Competitor'}>} [Competitor Price]),[Product level])

anything I miss? 

thanks