I'm under the impression that you don't "go off SSDI for TTW" and then try to "get back on." TTW is a benefit while you are on SSDI to see if you can tolerate working again. If the part time work attempt fails, you just continue on with SSDI.

Some people have expressed the concern that a seemingly successful work attempt (say, working for nine months but just under the SGA limit) would then trigger a review. Proving that you can work a certain amount, but no more, sounds (to me) even more difficult than proving you can't work at all. If the work attempt was a clear failure (ie, you find out that you can't tolerate working and your condition worsens or you have to quit/get let go after a short period of time), I don't believe that the SSA should hold that against anyone as it is evidence of their disability.

I don't recall that any of the regular posters here have tried TTW, but several are very knowledgeable about the SSA's policies.

Best of luck in your attempt to try to work again.