Hi Robin.
You can use the MUST command both in individual tcodes (CKMH or in CKMLCP.)
by the way, there is no sense to run ML Closing if you done change MM period, i mean
MM Period must be greater than the period you are closing in ML, you can review the details in FM CKML_F_GET_SL_PERIOD_INFO (i just did a fast debug with MUST_SETTLE), its not simple to understand the code because system assing 2 letters in this FM depending on a case and then do the validation.
Are you sure other consultant do ml close in 2013/02 but MM period was 2012/12? there is no logic in this statement because in 2013/02 there was not GM relevant to ML in this period.
Now, the question is, why you want to close ML if you still dont open MM period ?
I guess you can close every month from 2012/12 without any kind of problem.
Or maybe you want to set status 70 close to all of your materials? you can do this with CKMHELP program, but im not sure if the program also validate if MM period is greater than the period you wnat to close in ML
Please, give more details about what you want and maybe someone can give you an advice.
Arturo.