I was recently granted SSDI, but they set an onset date two years later on what I submitted. I called SSA and asked for an explanation on their date selection. I understood that if they changed the date, their rules require a pretty detailed explanation and I got none. I was told by the SSA rep that I can either accept the date they selected or I can appeal. I would just like to know their rationale for that decision so that I can make an informed decision on an appeal. There were no events, tests, or new diagnosis anywhere close to the day they selected. How can I obtain that decision rationale without having to pay $82 to sift through things that I probably already have.