normally I do the 90-day report on the same day when I am also doing the yearly extension. However it is pure coincidence that both dates match: I enter Thailand on October 2 and leave Thailand in mid-March . . my Extension is due on January 4th. I go to Immigration on December
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and apply for Extension, Single Re-entry Permit and the 90-Day report all on the very same day . .I have been doing this for the past 14 years, no probs so far