Transmitting from a "fixed station" on 467 main channels.

[WQYC236]

Excellent points from all concerned! LOL!!

[WRAF213]

Well, here's my interpretation:
One goal of GMRS regulation is to ensure reliable communications between two parties, who are likely fairly close to each other. Mobiles and portables experience highly variable propagation, so adding a repeater effectively gives one side of the conversation coming from a transmitter similar to a fixed station. Fixed stations aren't subject to this propagation problem, so in this original use case for GMRS, a repeater shouldn't be necessary; it would only congest the GMRS channels further. Handhelds and mobiles, being close to the ground, should have shorter range than a fixed station, and a repeater should have longer range than a fixed station (to account for the variability of the portable/mobile stations). Since both fixed and repeater stations should have a long range, two channels would be in use over a fairly wide area. Therefore, it would be in the FCC's best interest to limit the number of channels being used by a single conversation with long range transmitters. While the rules may be confusing, or just outright weird or unfair, there's a logical explanation, and that's to maximize channel reuse (in theory).