Hi there, I sent an e-mail to the author of the article but I receive a reciepient error hehehe. You're right maybe it's an April Fools day :)

From what I understand the fine is UP TO QAR 10,000.

If you have 5 days overstaying after the 3 month extension of the RP expiry, you will just have to pay QAR 50.

Thanks again.