You have that backwards, my friend.I don't believe using or not using PL on the voice portion of F1 dispatches has to do with being patched to the P25 system. Camden County simulcasts their F1 (154.430) on the P25 system and they only use the PL when the tones are going out. The voice portion has no PL so you can hear it without having to listen to the tones.
No PL transmitted= you do not hear the tones
PL transmitted= you do hear the tones
I really wish they'd go back to the silent days. The tones annoy the crap out of me and I'm not certain why, I've been using and listening to these things for 45 years. Perhaps I'm getting cranky in my old age