What are the differences between the Retirement O visa and the Retirement OA visa in Thailand?

Then is t the Non-OA the much better option I feel it doesn't require to have money in the bank?

And can the OA be extended after one year?

I want to convert OA to O can this be done

Non-OA is a 1 year multiple entry visa that requires health insurance and can ONLY be obtained in your home country or country of legal residence.

A Non-O based on retirement is a 90 day single entry visa that can be extended 1 year. It does not require health insurance and can be obtained in most countries and from inside Thailand (transition from a tourist visa or visa exemption). The initial 90 day Non-O requires proof of 800k baht, but the 1 year extension requires 800k baht in a Thai bank account for 60 days before you apply for the extension, and you cannot remove the money for the duration of your stay (you can, but you won't be able to renew the extension).

And you don’t need the 800tsd THB on a Thai bank account

O-A has slightly different application criteria such as health insurance. But if multi-entry you get a one year stamp each time you visit the kingdom during the length the O-A is valid. This mean you can have two years of stay out of an O-A.