It's Rheem, and the discrepancy seems to be consistent across much of their line.
Coils have the same face area.
There is 200 more CFM on the 2.5 ton unit.
The locked rotor amps are higher for the 2.5 ton unit.
The 2.5ton requires a 25A fuse/circuit breaker. 25A breakers are an oddball size for many panels, I can't remember seeing any.
The EER/SEER ratings are similar for both units, which makes me think the 2 ton would have to use less power since it has less output.