I think the problem arises from people's confusion over what is stamped in their passports, a 'visa' is normally issued outside of Thailand, some can be issued inside Thailand ie non immigrant 'O' visa as part of a conversion, but non immigrant 'O''A' can not be issued inside Thailand
an 'extension' to the permission to stay is issued inside Thailand, be it 30 days, 60 days or longer all 1,900thb.
I think the op is not making it clear what he has and what he wants, this makes it harder to give correct advice