@KC ****
you can apply for a 90 day report from 15 days before down until 7 days AFTER the due date. Once it's past 7 days late you pay a 2000baht fine.
Here's an example; IF your actual 90 day due date is on Feb 17th, you can apply in person from Feb 3rd until Feb 24th. On Feb 25th you'll get a 2000baht fine