Wrong, you can apply and get a 90 day Non-O from inside Thailand if you meet the requirements and the 90 day stay is stamped in your passport, no need to leave to activate it
It sounds like a Non-O Retirement Visa (for over 50s) is the Visa that best suits your requirements as it will give you 90 days on entry (single entry)
if these are seasoning requirements you need to state which Embassy or Consulate has the application requirement and which Immigration Office has the extension requirement