Annual check up with regular dentist

Had my annual check-up with the regular dentist after work today (not my orthodontist)......
He said I have EXCELLENT oral hygiene and can see that I really take care of my teeth..... BUT unfortunately 2 of my back bottom molars need a couple of little fillings. He said it is just caused by wear & tear and with there being a lot of grooves in those teeth that these things are bound to happen despite excellent oral hygiene!!! GRRRRRRRRR!!!!! He said it is definitely NOT from wearing my invisalign trays at all and it was actually spotted from my PRE-invisalign photos (the dentist that took the photos pre-invisalign put a note on it for my check-up to say that those particular 2 teeth needed to be watched). So, the good news is that it wasn't invisalign that caused the holes but the bad news is that I'm gonna be about $400 out of pocket!!!
Sooooooooo much money is going on my teeth!!! I have an appointment with the hygienist in a couple of weeks for a professional clean & that alone is $190!!!
P.S - I had my trays out for 3 hours in a row last saturday night, the longest I have ever had them out in one sitting! Oops!!!!! but I seriously don't think it will affect my treatment or anything! Will see when I have my next appointment with my orthodondist!