Bangkok is day before for bank letter, up to seven days before for bank statement, and bank book updated on the day (which can be done at CW, except for SBC, which does not have a branch at CW)
Maybe that's it. All I know is I've made about ten out-of-province ATM withdrawals using contactless and haven't been charged, and I don't get any text message.
You do it all online. My lady has done it twice for Australia, twice for UK and once for Schengen. All whistled through no problem. Need Statement from her employer, payslips, bank accounts and land ownership deeds.