I got this one. You need 2 copies of your bank book. The 400k has to be in there 2 months prior to you submitting for visa. Have the atm or bank clerk update all the information into your bank book
Then you have to get a stamped letter from the bank that the information in your book is correct. Make sure that document states it for the immigration department. Copy that as well. Fees vary, but I pay 100baht for the stamped document from bank.
or go to the real Department of Motor Vehicles. Watch a 45 minute movie and only pay 500baht. First issue is good for 2 years. Renew it for 200baht and it’s good for 5 years