@Mike ***********
When you apply for a O or OAVisa the first time, you need to show you have minimum 800 000 Thai bath in a bank at home. In one year you ask an extension, you have to show
*****
bath came in every month, first extension, you show 3 or 4 months (the most recent months) it's OK in Pattaya, after that 12 months. Avoid Bangkok Bank.