What are the requirements for using a combination of pension and Thai bank balance as proof of finances for a Non-O retirement visa extension in Thailand?

Hello everyone, does someone have any experiences with a Confirmation review of the pension notice by German embassy in Bangkok if someone wants to use a combination of his pension and his Thai Bank balance ( the sum 800 000 Baht in a year) as Proof of finances for a non immigrant O retirement visa extension at a immigration office? The non O , 90 day visa stamp is already in the passport while entered Thailand at Suvanabhumi airport.

Should the pension letter be in English language or Thai or it is enough in German language but approved by the embassy?

Thank you for any advice coming from people who really knows the matter and not just talking.

😊🙏😊