@John *********
This won't work. When you go to immigration the 2nd year they will want to see a 12 month bank statement, for 2 reasons. First they will be checking that you did the monthly transfers, and 2nd they will be checking that you met the financial requirements for the previous year's extension, which is that you must keep the 800,000 in your bank for 3 months after you received the extension and never let it drop below 400,000 the rest of the year. If the op uses an agent, he clearly will not have met those requirements, and he will be denied the extension altogether for failing to meet those requirements. Some offices even tell the person that they've technically been on overstay from the day their account stopped meeting the mandatory balance their extension required. This is why people get stuck using agents year after year, because they cannot prove they met the previous year's requirements.