Using Variables in Set Analysis Expressoin

I use the following typeset analysis and it cannot return data.

=Only({1<Month={"$(vMonthNr)"}>} Minutes)

Where: vMonthNr = Month ('$ (vFromDate)')

I tried using a variable with a fixed value. in this case it works fine. see expression below.

=Only({1<Month={"$(vMonth)"}>} Minutes)

where vMonth = 4

The variable "vFromDate" takes its value from the calendar extension. and the Minutes field comes from this Data.

[Table1]:
LOAD * inline ["Month", "Minutes"
        1, 12000,
         2, 12600,
         3, 12600,
         4, 12600,
         5, 12000,
         6, 13200,
         7, 12600,
         8, 13800,
         9, 13200,
         10, 12000,
         11, 13200,
         12, 12600,];

If the variable has a simple value, it works, but when the variable has an expression, it does not work.

Please note: I tried to apply the answers in this Question ( QlikView - Use a variable in an expression for analysis) , but, unfortunately, this did not work.

Thanks in advance.