Rolling 12 sales from end of selected period

[C_Howarth]

I am trying to write a expression to calculate Rolling 12 sales from the end of a selected period what I have so far is:

sum({<[flag sample] = {0}, distributor_flag = {0},month = , [month description] =, Date = {">$(=addmonths(max({<[month code] = {$(=(Year(Today())&GetFieldSelections([month])))}>}[date]),-12))<=$(=max({<[month code] = {$(=(Year(Today())&GetFieldSelections([month])))}>}[date]))"}>} [oneforce sales] * [exchange rate])

When i dont include the "Month = " part it obviously only shows me the sales for the 1 selected period however when I do include it it is bringing back heavily exaggerated sales

any help is greatly appreciated

[C_Howarth · Accepted solution]

solving my own question again but noticed that I was using the Date function rather than [date] field