I was wondering when approving for an extension on an O-A visa,do they base the length of the extension on the stamp or on the dates on your insurance coverage? I already have insurance coverage which will cover the requirements but because of leaving and coming back in March, my permission to stay stamp dates are screwed up..( got 17 as opposed to 23/24 months out of original O-A) with my insurance dates...
TLDR : Answer Summary
When applying for an extension of an O-A visa, the extension length is commonly based on the duration of the insurance policy you hold, rather than the permission stamp dates. Immigration will grant an extension only for the time your health insurance policy is valid, which must be from one of the approved Thai insurance companies.