Not necessarily. I sold my 2021 Merc GLA via Motorway in Sept. The online quote was £37300, but the final offer I got was £38600!!!... I bought the car last year's Sept for £35.5k, a tidy profit of £3k after 1 year and 8000 miles. Not bad!
Tesla trade in offered 33.5k, and WBAC offered £34.5k...