The newest police order put out (which takes effect on March 1st) spells out totally NEW criteria for people getting yearly extensions of stays based on being over 50 using banked money.

You now need the 800K baht in a thai bank account in your name only for TWO months prior to you applying for your extension, AND for 3 months AFTER you get your extension, THEN the money cannot drop below 400K baht for the remainder of the year.

I am guessing they will give a 3 month "under consideration" stamp when you apply for your extension making you come back with an updated bank book to show the 800K baht is still in the account after 3 months and then ink the rest of the 9 months extension into your passport
AND the following year they will look at your bank book and make sure that at no time did the balance drop below 400K baht.

I won't link to the article as it's from the Thai Visa group, sorry for that but they broke the story.

It is already getting a LOT of blow back from foreigners AND immigration officers alike. Conveniently the person who signed the police order has been "unavailable for comment" since the breaking of the news.
New Retiree Visa Rules Bewilder Thai Immigration: Source