I know if a claimant applies for SSDI/SSI after their DLI has expired, they may still be eligible for benefits as long as they can medically prove their disability reached a qualifying level before their DLI. Considering my current claim status, I have been declared disabled. The only relevant issue now is determining my alleged onset date. I suffer from what is called a "progressive disease" while meeting listing 14.09C1. I'm curious to know the process of how my AOD will be determined and how far in the past will my AOD affect my monthly benefit amount. I last worked Sept. 2001; received LATE diagnosis Oct. 2003; DLI Dec. 2006; applied Dec. 2009. My treating doctors have provided MSS/RFC stating my impairment met the listing as far back as 2000 based upon the pathology of my disease.I know my maximum back pay would begin 1 year before my application date plus the additional 5 month period (roughly July 2008). What calculation is used to determine my monthly benefit amount based upon my established onset date? Even though I could only receive back payments beginning July 2008, would my monthly benefit amount increase if I could establish my onset date back to 2001? My annual Social Security statement estimates what my disability benefits would be if I were to become disabled per given year. Each subsequent year after I stopped working (2001), that monthly amount decreases. This leads me to believe the earlier I can set my onset date, the larger my monthly benefits would become. Is this how monthly benefits are calculated given my scenario dates? I have medical records all the way back to 1989 showing the disease progression.