"The extension process can be completed up to 90 days before the current visa expires." I think in reality you'll find each place has it's own rules. For sure in Hua Hin it's 45 days. My neighbour was refused a few days ago because he applied too early.
I believe you can only apply when you have 45 days left on your existing visa. A neighbour of mine tried this same thing a few days ago after only being here three weeks. They told him to come back later.
The pink ID card was never mentioned in the original post. I think the SCB made that yellow Book rule up on the spot just to piss you off. This statement ..... "Saves wear and tear on your passport" is laughable.
I'm told it has to be on the day. You go to the bank, make a transaction, ie put 100 baht in. Confirm that in your deposit book with an entry stamp, get your letter saying you've had 400k/800k for the time period and off you go to immigration and show that you've still got it.
Sounds like the daughter back in Thailand held a bit of sway. Many jobs in Thailand are cash in hand and difficult to prove you actually have a job to come back to. Pay slips go a long way to help with this.