you are on the right track Mary, but it 2 months before your extension and 3 months after your extension that the 800K has to remain in the bank, and you are correct it must not drop below 400K during the rest of the year.
in my opinion also, but I am happy with my Non O based on marriage to a Thai National, have been on it for years, and this year we clock up 37 years of marriage.
I think you mean options, correct. You have only one option if you are on the Non OA that is use one of the recommended insurance companies to purchase your health insurance, as I mentioned above the Non OA doesn’t allow you to self insure.
yes, but I said you cannot go from the Non OA to the Non O in country, you advised the OP in your reply that they could switch visas, without mentioning they must leave Thailand to break the chain of the OA , just be a bit careful when giving information as your reply was very misleading.