Well put it this way, i know of an insurance approved bodyshop near me that managed to turn a cracked front bumper and a tiny, tiny almost unseeable paint chip on the front edge of a bonnet on a mk2 punto into a near £1700 bill through insurance.
They charged for an initial inspection, a basic engineers report, a further diagnostic report including putting the car onto a jig to measure chassis alignment (there was no danger anything was out of alignment, it was a 2mph impact that hadn't even reached the slam panel, let alone bent any metal anywhere), a further engineers report upon findings, Parts (new from Fiat), prep work, painting, fitting plus VAT. That wasn't including any work they would have decided to do should the jig reading be out (and of course, it would have been.... easy money, can't be questioned)
Total amount of actual damage for a low tech diy fix of glueing the bumper and a chip stick was £20. (and yes, i inspected said car and bar the bumper, there was zero damage behind, everything was straight, it hadn't even touched the radiator, the fins were all pristine!)
Bodyshops are a total scam when it comes to insurance. They will get every last penny they can bleed when they think they can get away with it.