To be fair unless I saw official communiques from the bank I would not be taking the response from one bank clerk as gospel. If you asked a number you would get a different answer from each. You just said you asked 2 and got 2 different answers.
When you say research on your own what do you mean by that. Online or physically on Thailand with Thai subjects or organisations. You are still not being clear.
You need to look at LTR. The DTV is not relevant in your position. Biotechnology and other medicinal domains are target areas for Thailand. Look on the BOI website. In what area of Biotech are you experienced?
I used this one and they did everything. Gave us a pack with everythkng required for DLT. They will also do it again for buying a vehicle. Changphuak Gate Driving School Chiang Mai
If you are taking test at driving school then better to let them get both your Medical and Residence Certificate. It will cost only a little more than running around yourself.
Padkrapow4549 I once had a long chat with a "Head of Consular" at an embassy (Not Thai) while watching football for a few hours. Basically he said exactly what you are saying - it is up to them and he admitted bias can slip into decisions. It was due to myself and Thai partner being invited to a wedding but there was no chance of her ever getting a visa. We chose not to even attempt it. Same came up again 2 years ago. Invited to a wedding in another country and just could not be arsed to apply - I went alone.