Do I need to return to show my bank balance after my retirement visa extension application?

You don’t have to

surely you do whatever they say or dont say

okay, the way the seasoning of funds for banked money method on a retirement extension is this

the 800k baht has to be in a thai bank account in your name only for 2 months BEFORE you apply for a yearly extension, it has to stay in the account for 3 months AFTER that extension is issued and then the balance can't go below 400K baht the rest of the year (until you take it back to 800K baht 2 months before the following year extension)

You said you never "seasoned the funds" but then you say it has been above 800K the whole time 😮 So whether you knew it or not you HAVE met the seasoning requirements 😛

Obviously if they didn't tell you to come back then you do not need to.

nope, if they don't ask you to return when you apply for the extension you don't go 🙂

They were having people come back after 3 months to show the 800K baht was still in the account (to meet the changed seasoning requirements of 2 months before/3 months after) but most places discontinued it

If they didn't tell you to show up, you don't need to (BUT of course you still need to follow the seasoning requirements 😛as they will look at your year transaction detail print out NEXT year to see you kept the terms )