This is hugely confusing for me to comprehend.
The latest requirements for the extension which you posted, state "100,000 USD or 3,000,000 baht". The figure is mentioned in paragraph 6 of the Police Order: "3,000,000".
For those, like me, who must self-insure because the insurance company partially or totally denies coverage, the amount required to be on deposit in Thai banks is 3,000,000 baht according to paragraph 6.3 of the Police Order.
I cannot find any mention of 3,500,000 baht in the Police Order. If the Police Order truly dictates the requirements for the extension, then the requirement is 3,000,000 baht -- not 3,500,000 baht.