This exactly. Immigration have been very quiet on this. I guess we might only find out when someone applies for an extension and fined for not dong a 90 day report. The TM30 might also be a factor - no extension at Jomtien without TM30. In fact no 90 day report at Jomtien without TM30.
I use it as my 2nd account. Transfer money in there when going out or day-to-day expenses. If I lose the card or someone ever steals from it never more than 20k in there. They are quite efficient and last time when a big queue they put me in a meeting room out of the crowd - strange as I say never much in there.
Bangkok Bank on Pattaya Klang close to Big C seems to be a favourite with agents. Go I there and you see at least 4 of the well known names there in their company shirts.
It often depends on the bank too about what you can get done at branch. Bangkok Bank I had an account in Pattaya and in Bangkok they told me I had to go to the branch. I just opened another account (was on WP etc) with the branch who told me and completed what was needed - never used the account again 😉 Krungsri I have not had anything yet where I need to go to the original branch where it was opened. It is up in Pathum Thani and it was would be a pain in the backside if I had to go there. now I am not working.
Residence Certificate issue depends in the immigration office you are dealing with. Bangkok yes you need 3 months. Jomtien you do not need to wait. As with many things in Thailand "It depends". Giving definitive statements often trips you up.
There is no problem transferring any other visa from an old passport to a new one. I have done it in the past and takes minutes. Do you think they are making a special case for a DTV?
I am same opinion as you. It would be difficult foo agents to have contacts in multiple locations. Would have to be where a letter showing a recent balance was fine.
I think different Embassies and Consulates have different requirents. Some need the 500k to have been seeded for example a few months and other it just needs to be there at the time of application. There seems to be no standard like with the Retirement. Agents putting in money for the retirement put it in the applicants own bank account in Thailand. They are with the applicant the whole time at the bank ie they transfer the 800k into your account at the bank. Go to the counter and get a letter from the bank showing the money. Transfer the money back out to there account right away. At no point does the applicant have the opportunity to access those funds. The bank, immigration and agent work together in a specific locations. Doing this for the DTV would be logistically more difficult. Which bank receives the money? Is it a Thai one? Not saying it is impossible but it is more difficult. Are agents working with specific staff at the place of application?