Yes, unfortunately I was caught completely off guard by what the IO told me. I was even rather shocked, because until then the embassy letter had always been accepted without any issue. At that moment I wasn't thinking of all the implications, so it never occurred to me to ask whether switching to the 800,000 THB method would avoid any retrospective check of monthly transfers. I also don't know whether, if I switch to the 800,000 THB method, I should still provide the French Embassy income verification letter for the previous year. Obtaining that letter would not be a problem if it could help. Perhaps the best approach will be to go back to Immigration as soon as I return to Bangkok and ask for clarification before transferring the 800,000 THB. However, I don't think it is possible to book an appointment simply to ask for advice, and I doubt that the staff at the information desk would be able to answer such a specific question.
