Similar experience here with the Service Center for Europe in the Netherlands.
Sent in a Perdix AI, bought in 2018, only 150 dives, well taken care of, not a mark on it, that suddenly acted up. (Most probably the pressure sensor.) And my wife's Teric with a draining battery (well used, working 100%).
The Perdix AI was diagnosed as a total loss. The sensor is faulty and hard wired to the main board. New mainboards are no longer available as the AI is EOL. An upgrade to a Perdix 2 Ti was offered at a substantial price. A bitter pil, but understandable.
The Teric needed a battery exchange. (Cost quoted on RMA form @ €150,=)
After some time my wife was notified that, after installing a new battery, the mainboard displayed errors (battery overheating among others). Therefore the mainboard needed to be exchanged. (Cost an additional €145,=, also the battery exchange price was upped to €165,=) She called the Service Center and spoke to the service engineer. He told her the errors were discovered during the final checks. He is unable to check for mainboard errors before exchanging the battery.
I'm not a service engineer, but this last part sounds strange to my ears. (One can always enter a service menu can't you?) I'm guessing something was messed up during the battery exchange, which then caused the errors. If that is the case, I don't think my wife should be the one paying for the new main board.
I have since emailed Shearwater about the above, and am currently awaiting their reply on this.