are you sure? The advise I received says you will pay the difference. For example it you pay 10% in you home country and Thailand is 15% then you will pay 5%
I have a Bangkok Bank account opened in Airport Plaza in Chiang Mai y myself and a Kasikorn account which I opened in Cha Am. Didn’t have the smallest problem opening either. The Kasikorn account I use for housekeeping and was opened with 2000 bts and never had more than 10,000bts deposited