Bangkok Bank still in the dark ages. Having to get a 12 month statement (in CM for visa renewal) that takes a week and can only come from Bangkok is just one of many gripes I have with them.
I’ve just been through the same issue. My 90 day was automatically expired by immigration on the same day my visa was due for renewal. So I renewed my visa then went online and renewed my 90 day report. So in my case it wasn’t linked to my original date of entry.