Variable as Field and Value in Set Analysis Not Working

[rougeherring]

My Set Analysis is not working properly. A variable (vPeriodType) is set to equal the field [Year]. Then another variable is set to equal the maximum value of that field vPeriodTypeMax = Max($(vPeriodType))

vPeriodType = 'Year'

vPeriodTypeMax = 2021

I have test the variables above and get the values I'd expect. The following set analysis is not working.

Sum({<$(vPeriodType) = {"$(vPeriodTypeMax)"}>}NET_SALES)

It evaluated properly in the bottom and if I switch the value to 2021 manually, it works. It's just now working if I used the variable as the field value. 

[Lisa_P]

The double quotes are not relevant here, try this:

Sum({<$(vPeriodType) = {$(vPeriodTypeMax)}>}NET_SALES)

[rougeherring]

I was able to get the following to work:

Sum({<$(vPeriodType) = {'$(=$(vPeriodTypeMax))'}>}NET_SALES)

Please let me know if I should have any concerns about using this method. Thanks.