"the downside is - - - you have to pay the agency every other year. If you decide to join the agency tea money system, there is no way out if it".
Your exact words which are unsound and improper. You are generalising which is of no use to anyone. I suggest you take up an alternative means of filling your time.
Your bank statements and verification letter from the bank need to be dated the day of your application. A copy of your bank book showing a transaction on the day of application is also required. At least that is the case at my office. Also copy of tm30 and tm47. I would advise you to ask your office for a list of requirements and ask the Offucer to write down what they need from the bank in Thai to avoid confusion and multiple visits back and forth. Sign everything in blue ink at the bottom. A map showing where you live is another requirement and for me a Google maps print out was acceptable. Take copies of everything relevant just in case. They should provide the application form and declaration (tm2) I think but you can download them and fill them in before you go to speed things up. Dont forget two recent passport photos. Good luck.