From personal experience.
I applied for both SS retirement and SSDI at the same time. I was not working due to disability when I turned 62, so that determined when to apply. SS retirement was paid at the reduced rate for 62, until the SSDI was approved, with a starting date earlier than the day I turned 62, and obviously earlier than the date that SSA started paying retirement benefits. The SS retirement benefits already paid were deducted from the retroactive payment(s) for SSDI (I had to appeal to get an earlier effective date for SSDI, and was successful. The SSDI payment is the same as the SSA retirement would be if you retired at the normal retirement age, and, so I'm told, convert to SSA retirement when full retirement age is reached.
The only difficulty you have in claiming benefits is that you are currently working. If you are not working full time, you MAY (income limited, other requirements) be entitled to reduced benefits until you are no longer working. If you can also draw on a private pension, your benefits may be reduced further. (lots of complicate rules in this area).
QUOTE (Cavtrooper088 @ Jun 13 2009, 05:02 PM)

Hi gang,
I've got a question regarding SSI verus SSDI. I am currently 90%
(70% PTSD-numerous other 10-20%), and will be 61 in a few months. I'm still working, but am struggling with PTSD related issues. I've heard that once you hit 62 and are drawing SSDI that the dollar amount will revert back to the regular SSI that you would normally draw at 62. Can anyone clarify?
Cavtrooper088