In my opinion after applying in Ho Chi Minh the 500K need to be in Your bank account at the time of application. Even they ask additionally to submit 6 months bank statement it was irrelevant that I had my 500k only for few days. The reason why they want to see 6 months transactions is not known. In my opinion is not relevant that You married or have children in Thai to apply for DTV rather than there should be another visa in Your circumstances but defo not so great as DTV.
it was in April and my work permit is till November . The reason for refusing multiple entry was not explained but I read differences between aplications for single and multiple and I believe single entry is for employment inside Thailand when multiple can be obtained for “business trips to Thailand”