DOT Physical

I hope someone can shed some light on this situation for me. I have had a class B CDL for 10 years and have had several physicals for my medical card with no issues. I recently got my class A CDL and was offered a job at a well known company in my area. They sent me for the physical and their doctor found out I have had back surgery and now wants all my medical records. I ordered and sent every record I could get pertaining to the surgery and doctor visits. The records are missing my release letters to return to work. I was fully released with no restrictions after surgery and no one can find the records. My question is why am I being asked for the records now and not the last 10 years when I have had physicals with my class B? Is their a difference between the DOT requirements or is it this company specifically pushing for this. I don't know what I'm gonna do if all the class A driving jobs require this and I can't get copies of the original releases. I asked if I could see the surgeon and have him check me out and sign a new release and they said they still want the originals. Has anyone else ran into this problem?