I do have a Time Savings account (6 month term) at Krungsri bank. The funds are accessible if needed. As mentioned previously taking funds before the end of term will cause you to lose interest and penalty fee applied.
however, worried or not you will need the TM30 when you go to immigration for the certificate of residence.
If you are staying at a home you may also need a copy of the 1st page of the owners Blue Book and the owner ID card. It is likely you will need a copy of your Thai Cell phone bill that matches the number you are using to open the account.
The suggestions here advising go to the bank first and ask about requirements sounds like good idea to me.
understood, this is why I waited to the third year with a agent handled extension the second year but with all my 800k funds in the bank the entire year prior and 800k funds the entire year following the second extension. And I had opened a second bank account and banked the required 65k per month for the 12 months prior to the third extension.
Can be accomplished if the total prior history meets immigration requirements.
I apparently was also lucky. First extension was handled by and agent. But the last extension I put together the document package without agent assistance and extended with no issue.