my most recent understanding is you can do 90 day reporting seven days before and the day after you are considered late.
Make sure you have a TM 30 filed within 24 hours of your last entry. And go to immigration first time to file the TM 47 after that file correctly you will be able to online..
I understand your point. I do not know what Thai Immigration would require when switching back to the ‘proof of funds’ method. Where you about to find the guidance in Thai Immigration documentation somewhere?