How does the monthly income requirement for a marriage visa in Thailand work?

I ask because if you're from a country whose consulate issues the "affidavit of income from abroad" notary document you have to use that as proof if you are using monthly income method

BUT

If you come from a country whose consulate doesn't issue the notary document anymore (US, UK and Australia) or never did issue it, IF you want to use monthly income method for proof of funds, you have to transfer IN to the country in a thai bank account in your name only a minimum of 40K baht a month, each month every month for the preceding 12 months before you apply for your yearly extension.