What type of bank account is acceptable for 800k or 400k funds for visa extension in Phuket?

I have read several comments recently relating to the parking of one's 800k or 400k (for renewal of extension of stay based on being 50+) where immigration officials have declined extensions because the money was in "the wrong type of account." Does anyone have official details of what kind of account is "acceptable" or is this another office by office thing? I am in Phuket so anything relating to here would be most appreciated. Thanks