In the past, I have had cars that should have been totaled but were not. The reason that the First Quote was close to the Totaled amount but the second Quote pushed it well over that amount. So, the Insurance Company approved the new amount since they had already paid out for the first set of repairs and at that point it was "Cheaper" for them to fix it rather than total it.
I have had this happen to a lessor extent several times and am starting to think that some Body Shops do this on purpose as a totaled claim does not make them any money.