Hi,
I have an idea for you. Create a calmonth variable and keep it in filter pane of your query. Create KFs for calculations of MTD, QTD and YTD in KF pane. Keep QTD and YTD as "Hide can be shown" in display properties of your Kfs.
So user executes by entering the calmonth variable and it will calculate MTD, QTD and YTD in one shot, but only MTD will be displaying in the result by default. Thus, user can choose QTD and YTD if he wants from the Kf dynamic filter.
Regards,
Suman