@Wayne ******
For combined method, the rules seems to stay the same, for at least 3 months after application the full amount and the rest of the year not less than half.
As you apply for a new Extension you must have at least 2 months prior application the 400.000 Thb on the bank or use an income affidavit from your Embassy, or if they do not provide, at least 12 months prior application a monthly foreign deposit of at least 40.000 Thb into your Thai bank account.