It is not just DTV holders get pulled at the airport though at CNX. Visa Exempt and Ed get it too. It is just a sample of entrants though - not everyone is getting questions.
I have dealt with Bangkok, Jomtien, Chimchurri Square One-Stop-Shop and now Chiang Mai over the years. CM definitely the easiest to deal with - it may just be the volume at the others but CM seem better prepared up front. The requirements list they give you are spot on - they even explain it to you and underline what they see as most important. Having a drive through for 90 Day is very convenient. All you need is passport and TM47 as what else is really needed - everything else is on the system. As you say service levels vary widely and they are run like little fiefdoms. Some are very profitable :-)
Yes - bank book from same bank but branch in Bangkok. Retirement "O" Visa. Previous time I asked wanted Residence Cert etc but this more senor lady said no need. She had just completed all of my bank requirements for visa renewal
Lokks like the ATM fee has gone up to 250 THB but you can get 30k out at a time. I have a couple of bank accounts but pay for shopping and drinking & eating in cash. Only really pay bills like phone, electricity in Thailand online.
The thing about Chiang Mai is they are sticklers but also the most helpful office I have dealt with. Double edged sword 🙂 At the office they have 2 desks to ask info and also have graduate trainees walking around looking to help. After they help you feedback is asked for and an app.