MRC book setup with different calendar than primary book

 If we have a user asking for an MRC book in the same currency as the primary book because they want to use government defined rates, and they also want a STAT book for a different calendar, can we just set up the MRC book with a different calendar and define the conversion options to use the govt rate?

I thought I read or was told that as long as you are only changing one of the 3C's that you didn't have to go to STAT, that MRC could be used in that case.  I found that you can have same currency MRC but I did not find anything around the calendar requirements between a primary and MRC book.