Here’s a couple of other reports of suspicious justification to lower Apple trade-in values. My concern isn’t the $250 I lost in trading in a five-year-old phone, it’s the loss of trust with Apple’s trade-in process.
The Verge from 2021: https://www.theverge.com/22368541/apple-trade-in-phobio-macbook-white-spots
Reddit thread from 2022: https://www.reddit.com/r/apple/comments/snr3tw/beware_apple_tradein/