Soon I will be entering the seasoning window for my retirement extension. Will it be a problem if money moves to/from a fixed account during that interval?

I don't expect Jomtien Immigration to do any calculations. The letter from the bank will state that my deposits totaled more than 800k during that period.

I know use the Income afffidavit, but when I did use the bank deposit letter, the letter only stated the amount in the account, they used the copy of the bank books to determine if it had been in the bank for the required amount of time.

It should be no problem but one or two members have reported problems doing this.

Personally I would keep it as simple as possible.

Why give them an excuse?

Yes, why give them an excuse. I made the mistake of moving my bank account from one bank to another during the 3 month pre-reapplication period. Elapsed time between closing one bank account and opening another at the new bank was maybe 15 minutes. After lots of grief from a pissed off officer, (and the intervention of another officer who has known me for many years), it was finally allowed.

Don't give them any reasons for questioning your banking arrangements. Maybe it will be OK since you state your funds are with the same bank. TIT, though. If they feel like it, they can give you problems. I'd make sure by getting the bank letter to cover all your accounts and make sure the balances of all accounts are also photocopied.