Well, in my area, most of the departments and agencies try to keep the same PL. They all work on different frequencies normally, so there is no interference.
However, if a situation arises in which multiple agencies (township/city PD, EMS) have to communicate with each other more quickly than with a TX, they can simply switch over to a common frequency (chosen as needed), without messing with the PL's.
Anyway, to answer your question, most of our agencies use 82.5, but there are two that use DPL, one is 261, the other is 054.