It's 'at least' and your home country insurance is accepted as long as it covers you for hospital in Thailand. If you apply as a wealthy pensioner, be aware that the income requirement, must be passive income, not salary and wages, They'll ask for alot of evidence.
. Great information about annual report requirements. I did same calculations for my non immigrant OA visa. The OA is much cheaper than the equivalent LTR. 90 day reporting isn't a big deal. I do it online