linest_m always returns zero

[lukas_sokol]

Hi i Have a straight table with 4 dimensions Sales Area, Sales Market, Company Country and Company Name.

In expressions i have sum(Sales) and it's ok

for second i want to calculate slope for 3 last months.

I use

linest_m(aggr(

        sum({1<[Created Year Month] = {$(=vCreated_YearMonths)} >}  Sales)

        ,

        MonthsRange,CompanyQL,[Sales Area], [Sales Market],CompanyCountryNameQL)

,MonthsRange)

where Moths Range is (1,2,3)

and I always get 0, which is not true.

Regards

Łukasz