That fine seems high. I hadn't filed it at all, then did the Tm47 then the TM30, they fined me around 800 baht IIRC at MTT then I took that with me to file for a Cov19 extension. The 2000 baht is generally for the landlord. They lower the fine for individuals. But every situation is different and so is every officer.
Just so the picture is clear, I had a Non B visa then recently converted it to a Covid19 extension. If I am understanding this I can continue to go to CW for my next Covid 19 extension (2nd one after NonB) tomorrow