In your case it can be:
*SELECT(%Y%,[YEAR],TIME,ID=%TIME_SET%) // %TIME_SET%=2016.05
*SELECT(%ALLMY%,[ID],TIME,[YEAR]=%Y% AND [LEVEL]=MONTH) // %ALLMY%=2016.01,2016.02...
*XDIM_MEMBERSET TIME=%ALLMY%
*WHEN TIME.MONTHNUM
*IS 1
(Do stuff)
*IS 2
(Do stuff)
*IS (3
(Do stuff)
*IS 4
*REC(FACTOR = 1.1,TIME = %Y%.01)
*REC(FACTOR = 1.1,TIME = %Y%.02)
*REC(FACTOR = 1.1,TIME = %Y%.03)
...
but I do not understand the logic of your script... please explain what do you want to achieve with some sample data.
Vadim