Several things ...
Yes, 153.89 is a vehicular repeater system ("Pyramid" is the brand name) on all ACEMS ambulances that allows VHF portables to communicate through the mobile MARCS radio. The purpose of programming a "receive only" channel in the VHF mobile is to allow someone in the truck to hear a portable calling back to that truck. If one paramedic is in the back of the ambulance with a patient and the other is 100 feet down the highway talking to the state trooper and that medic calls for assistance, the crew member in the ambulance can hear that call. Without this feature, they hear nothing because the MARCS radio is in transmit mode. The crew member in the ambulance will hear the dispatcher's reply but that's it.
154.265 MHz is the Athens FD repeater output. At one time, "265" was supposed to be one of three nationwide miutual aid channels. They have never been used in southeast Ohio because most of the fire departments here are volunteer and operated on 33 MHz or 46 MHz low band (or used CB radios) for decades. I think you'll find most of the frequency coordinators just tried to find quiet channels for all these buildouts and upgrades. You will find base stations and repeaters transmitting on channels formerly reserved as 'mobile only' frequencies. You'll find Police systems on Highway Maintenance channels, et al. Nothing surprises me anymore. In any case, 154.265 works fine for AFD because there is no one anywhere near Athens using that frequency.
The county fire radio system is what it is. There is no logic or order to the mess and yes, they've spent a King's ransom over the years trying to make it work properly. The new 911 Director is a former Motorola service tech and he fully undertands what needs to change. They are looking at building out a single, county-wide VHF paging channel using syncronized transmitters. This way, all Fire, EMS, EMA, Siren Control tones can be broadcast on a single frequency. A number of agencies are moving toward MARCS (or talking about it) and there has been limited interest from several volunteer fire departments in building out several talkgroups for the VFDs to use. Of course, money is the biggest issue here. When everything is done, you'll probably see a bunch of VHF channels surrendered to the FCC for license cancellation.
Rick W8UU