on the other point I renewed my long term visa recently too and the immigration officers could not have been more helpful. I changed from banked money to monthly payments.
same here. If I want to bring in 3 million baht to buy a condo and 1.5 million baht to buy a new car that is 4.5 million baht that will not come to Thailand if I am taxed on it here.
so you are talking about last years extension in which case you are correct. To meet the terms of that extension you should have had 800k in your bank for 3 months after and not below 400k for the rest if the year. However, my office never checked up on that and just accepted the 12 monthly payments for this years extension.