you are talking nonsense. Immigration does not treat extensions as a report clock start. If I enter on a non-o and then leave and return after day 30 and then on day 45 of my non-o stamp I apply for my 1 year extension of stay my 90 day report is not effected by the extension. I still need to report 90 days after my last return to Thailand.
If you already have Thai bank accounts with significant history then you would be deemed low risk regarding KYC protocols. You cannot open accounts on a DTV and newly opened accounts have been shutdown but existing low risk customers should be fine. Why don’t you go into your branch and ask?
incorrect, 90 day reporting is due after 90 days in Thailand, getting an extension is irrelevant to your reporting requirements. Some offices may process the address notification at the same time as the extension and give you a receipt stapled in the back of your passport giving you the date of your next report, some offices don’t.