When I applied for SSDI/SSI in Dec. 2009, the FO agent mistakenly entered my AOD as Nov. 2009. This date was simply my protective filing date. I submitted an AOD of Sept. 2001 because that was my last day of SGA. On some of my SSDI documents she noted my onset date as Nov. 2009, other documents as Sept. 2001. She even noted my POD and EOD as Sept. 2001. These conflicting dates have never been corrected even after 4 years. The AC remanded my claim twice with instructions to correct my AOD (this never happened). I will soon appear at my 3rd ALJ hearing. They have already deemed me disabled, but as of a much later date because of this ongoing onset date issue. Neither of my representatives (first one withdrew) seem to understand the importance of a proper onset date, so I'm asking here.I have a progressive disease meeting listing 14.09C1. I have progress notes from 1989 documenting the progression of my spine fusion, etc. I have 2 fully favorable RFC’s from my treating doctors who opined my condition has been disabling since 2001. I have 3 MSS from my Rheumatologist explaining the severe and advanced nature of my disease. I believe my impairment is one of those that no one knows about, so no one is giving me the proper evaluation. Since the FO agent went so far as to “establish” my onset date as Sept. 2001, shouldn’t that trump all the other incorrectly written onset dates? For 4 years my claim has been incorrectly evaluated with an onset date of Nov. 2009. Once an onset date is “established”, how can the ALJ continue to use the other incorrect onset dates to my disadvantage? With a DLI of Dec. 2006, I would think there would be enough red flags to have kept this from happening.