Also not so straight forward an answer, equivalent hire car costs etc. also come into play which can build substantially if it's an 80k car, so doesn't really stand to reason its taken a harder knock.This is not a straight forward question and surely the answer has to be very dependent on the vehicle and the value of the vehicle when it was categorised.
So an 80k car written of as CAT N would have taken one **** of a shunt, whereas a 6k car might only have had light panel damage.
So it stand around reason one must take a much larger % knock on resale than the other.