VETS-4212 - How do you know if you must use MHL reporting by Hiring Location?

To file the VETS-4212, one can choose from 3 options:

MHQ = Multiple Establish. Headquarters
MHL = Multiple Establish.-Hiring Location
MSC = Multiple Establish.-State Cons.

I cannot find any definition of the requirements for those 3 choices - does anyone else know what the differences are? We run all of our new hires through corporate.  HR is telling me that we submit with one line of MHQ with the totals and then have the detail lines as MHL. If I run the R080436 with MHQ, the whole report is with MHQ; the same with MHL.... so I run it twice - once to get totals, another time to get details and then make sure they match... If you use MHL do you also have to have the total line for MHQ? seems weird to me.