My wife and I come here for six months each year - this is our sixth year. Each year my wife leaves the US on her US passport and enters Thailand on her Thai passport. When we leave she reverses the process. We always go through immigration together since we are married. No problems so far.
I think that you are confusing an extension of stay for the purpose of retirement with a non imm o-a multi entry visa. The non imm o-a is obtained in your home country via a Thai Embassy or Consulate. If you are currently in Thailand you would apply for an extension of stay based on retirement. That is good for one year. At the end of that year you will apply for a new extension of stay. If you wish to leave the country during that year you can purchase either a single reentry permit or a multi entry reentry permit.
agreed. It is transitional, in the sense that it is the only visa that one can obtain within the country and is used, during the last 30 days to apply for an extension of stay. P.S. Is the OP currently in Thailand? His bio has him living in Queensland.