Okay, it doesn't matter WHAT your coverage is or how long you've had it IF it's not from one of the 13 approved thai insurance companies you're NOT gonna get a yearly extension (from the immigration office) on an O-A visa. That is not a topic that is up for debate.
This lists the 13 thai approved providers;
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you either use one of them OR you go back and get a new O-A from a thai consulate in your country OR you "break the chain" from the O-A visa you have now by bouncing out and back in to get a 30 day visa exempt and then convert that to a 90 day Non-O visa inside the country OR you go to a thai consulate and buy a 90 day Non-O.
Those are the ONLY ways to have it work out.