Wrong 90+ furnace installed

[grEEnsolutions]

I would like to know the difference in equipment price of the Bryant CAV and Bryant AAV. (Install costs not needed.) My friend was quoted the CAV on his contract, that he signed, but instead the contractor installed the AAV. This seems like a breach of contract since the client party was not informed of a change of major equipment installed.
He has a 1200 sq ft space to heat and the ducting is already installed. He could not confirm the size of the unit. He did tell me the following rating: "ECM motor size115V, 68Hz 4000rpm 1/15HP." A sealing of ducts was completed and otherwise the installation was smooth.
Is there an expert who can explain the advantages of a CAV over a AAV? Does it lie with the temperature consistancy?
What actions should the client do in this case?
Any responses are greatly appreciated!

[beenthere]

The rating you posted is for the inducer, not the furnace.

The CAV is a multi stage unit, the AAV is a 2 stage unit.

He should ask his contractor why the swap. Its possible it was by accident. The contractor may put in the contract listed one or offer a small refund.

Pricing questions are not allowed on this site, So they will not be answered.