@Andre **********
it used to be two months for the first application, and 3 months for all other applications after. But the rules got changed in 2019. Now they do not make any difference if it is your first extension or a follow-up one. It's 800,000 in your Thai bank account for two months, and must remain at 800,000 for 3 months after the extension has been issued. THIS is the 2019 police order!