Do I need to prove foreign payments for my Non-O visa extension based on retirement in Thailand?

@Richard **********

if you entered Thailand on a 90-days Non-Imm-O Retirement Visa, you don't have to prove that the 800,000 THB deposit came from abroad, for the application to the 12-months Extension of the Stay Permit. This proof is only needed when you apply for the 90-days Non-Imm-O Retirement Visa on Immigration inside Thailand, after you entered visa-exempt or on a tourist visa. This process would be called "change of visa type". You probably mixed up these two different approaches to the Extension

I’m completely new here, but don’t you just need to show your bank statement giving the amount required ?

You don't need to prove foreign payments if you are applying for an extension using the 800k baht method