Already on 12 month extension.  Is there any flexibility on the extension, if paperwork for next extension is 1 or 2 days late, such as by paying overstay fine, or is the date fixed with no exceptions.

When 1st extend of my Non-B after 3 months, some paper work delayed and I can only submitted on last day late afternoon at WC. Which also on a Friday of Nov of 2019.

After my agent talked to the IO, additional 6,000 + fine for late to process and able to receive renew visa on the following Tuesday...

Technically you should fall under the amnesty but they apparently don't consider it as a valid extention. Normally you would be on a overstay at a 500 baht a day fine.