Coinbase Cost Basis blunders: Really CB?

I was doing my taxes and found out that Coinbase applied prices as of 11/30/2022 for cost basis when they transferred from Coinbase Pro to Coinbase. This is ridiculous given they should be able to give an exact cost basis. In 2022, crypto was doing good for the first half of the year and then went down for the latter half. I purchased ETH around April 2022 for around $3,000 which Coinbase transferred at $1,200 on a cost basis ( the price of ETH on 11/30/22). I sold my ETH in 2023 and Coinbase used 11/30/22 ETH prices for the cost basis. Had I not noticed that, I would have lost a couple of thousand dollars in extra taxes. This is not tax or financial advice but putting it out there for awareness.