Those codes are NOT definitive.

There are other things that can cause that- like vanos issues causing the car to run rich at some RPMs, leading to a swamping of the cat with hydrocarbons.

What do the AFR numbers look like over the RPM band? What are the results of a vanos functional test?

Looks like dealer pricing, eh?

I would NOT trust an Indy that is guessing with my money and just using codes....