I just came back from Vietnam yesterday.. after receiving my approved dtv. I subbed my TDAC stuff day before my flight yesterday.. its instant approved or declined.
FYI if you get your dtv you get a visa number on the doc. Incl that # in your tdac app where it says visa number..
yes I went with #FitFac. They have like 12 gyms all over Bangkok.. and they took the time to make sure I'm had all my docs and I paid the little extra for their application services similar to what Siam offers.