@Manfred *********
yes, I think that is the reason. I read anecdotally that the 800k was introduced because historically foreigners came to Thailand with little money, had no insurance, got ill and Thailand was left with the medical costs. Foreigners now have a choice between the non-OA visa that requires the mandatory insurance, criminal checks etc, but no need to deposit 800k in Thailand OR the non-O that requires a deposit of 800k in Thailand. They can both be applied for outside Thailand.