Ahhh. the long & sordid tale of the Franklin Twp TRS:
Franklin was originally going to be part of the full greater countywide TRS, but the county would not promise in-building coverage on portables that would meet the PD's requirement for officer safety, so they built their own site. This next part is purely conjecture & was always part of jokes from the technically-inclined - it was said they had to have all the digital bells & whistles + encryption from the start, so they couldn't afford their own system controller (hence the Franklin site sharing the county's SysID). Franklin completed their build-out ahead of the main county system & went on the air first.
Then, after a few years, the FCC told the township they had too many assigned frequencies for the subscriber load that was actually in-use (it used to only be the PD). So the township went out & got radios for all the FD's & squads. Line officers had XTS2500's that were fully flashable to handle future P25 upgrades, but there were/are still many XTS1500 portables that can never get the P25 flash without having to have all SmartNet/SmartZone features purged from the device to make room for the P25 functionality.
The township just doesn't have the funds to completely re-do all the radios currently out in the field for all the emergency service agencies, hence the reason why the Franklin Twp. site remains Type-II, but still controlled by the county core (the same reason that NJSP talkgroups show up on the NJICS - shared back-end hardware).