Hello! Just confirmed with Beth Tapp, director of Purchasing Services (relocation policy is hers)...
Don't
use per diem: units may reimburse actual meal expenses for the new
employee + dependents while in transit and the amount has to come out of
the total for relocation that was in their appointment letter. (It
cannot be in addition to the relocation amount on the appointment
letter.)
Also a heads-up that an update to the relocation policy in the works, so please watch for announcements about it.