You can apply for an extension when you have 30 days or less at all immigration office, and 45 days or less at some offices. There are no offices that accept an extension application 3 months ahead of time.
the extra cost is when people use an agent and don't want to show any money. The agent takes your money and greases the wheels at immigration so they look the other way about the fact you aren't showing your money in the bank.
You could use the same 65k each month but it doesn't make much sense. You need money in Thailand to live anyways. Just use it for your daily expenses.
There are some immigration offices that require you to also show "where the money came from" as in they want to see documentation of a pension or retirement account as well. But that's rare.
This is a "multiple re-entry permit" that is valid until 14 July, 2026. If you look at your extension of stay, that should also be valid until 14 July 2026. That's how re-entry permits work, they are valid until the end of the stamp you purchased them for.
Basically what that means is that you can leave and return to Thailand as many times as you want (multiple) until the end of your current extension. You would need to be back in time to apply for your next extension, at which point you would need a new re-entry permit if you want to leave Thailand.
There is no ongoing 90 day cost. Maybe your friend was using the agent to do his 90 day reports, which would cost additional.
Officially it is 2000 baht for the 90-day non-O visa. And then after that it's 1900 baht per year for the extension.
If you use the bank deposit method, the balance must remain at 800,000 baht for 2 months before your extension, and 3 months after. It can never drop below 400,000 the rest of the year. So that's 5 months per year at 800k and 7 months at 400k. Most people just leave it at 800k so they don't time it wrong and ruin their ability to get an extension.
But many people also start sending 65,000 baht per month to their Thai bank account from overseas during the first year. This allows them to switch to the income method for year 2 and onwards, meaning they don't have to keep any money in a Thai bank account. Each year they just have to be able to show they receive 12 months of 65,000 baht from outside of Thailand to satisfy the income requirement.
The "cost" of a retirement visa in Thailand is 2000 baht. Annual extensions cost 1900 baht.
But there you must also be able to meet financial requirements. One of those requirements is 800,000 baht in a Thai bank account or 65,000 baht monthly income. Most people are not able to use the monthly income at least for the first year, as immigration will only recognize embassy verified income. Many embassies stopped providing this a few years ago.
Please show me this news. I've never seen a single article about that happening and it was from the bank itself. You're just making stuff up and propagating unfounded rumors.