Residual exchange: reject offer ?

Hello, after an economic total damage my car was put into a residual value exchange, the offers were very different, but moved almost all within a certain framework, however an offer was about 4000, EUR higher, which actually does not make any sense or but the dealer has already had various parts in stock. Now I have heard that the expert can also reject the first offer, is this true and if so under what conditions? My second question would be, that for example 10 offers are at 4000,- EUR and one only at 8000,- EUR, is this one offer then really representative ? In my case times concrete figures: WBW: 10,000,- EUR residual value 8x 3000-4000,- EUR offered, 1x 8000,- EUR damage is over 11.000,- EUR Thank you