Like John B said, the input PL's vary by repeater. Regarding the FF Service, the input PL's are 179.9 for the main repeaters for the Divisions, but from what I understand now, there are "fill in" repeaters, like mentioned earlier. I don't know what the PL inputs are on these but have heard Division A (North) say on the radio: Ch 7 North, Ch. 7 South. I hear them on my radio fine with a PL input/output of 179.9 Hz. Channels 1 (DEP Main) and 3 (Fish/Wildlife) uses the different tones for the section they can hit the best with their radios. So, in the event of SE Sussex Co., you would hear the mobie side like this: 159.3450 PL 131.8 and repeater (both sides) as 151.3250 PL 179.9. Unless your interested in finding out how close the unit is or for radio programming, there is no need for the PL codes by repeater. They all output 179.9 Hz. As mentioned earlier, the "A" channels (Fireground) output 82.5 Hz. This way, they by-pass the repeater and make it a talk-around while minimizing the need for additional channels.
Now the mystery is what is the DEP frequency 159.4350 used for? My guess was that it was an old DEP Marine PD Channel, but have not confirmed it.