Ok. So as you all know immigration offices are closed until Thursday 17th. For many offices they will be absolutely chaotic on Thursday. If you can avoid going to immigration on that day then please do so.
If your entry stamp or extension finishes between now and then, then go on the 17th and be prepared to wait for a long time. You won’t be fined because of closure but will get an overstay stamp.
Friday will probably be crazy too because of the fallout of the 5 day closure.
Going to immigration early is usually a good idea for most extensions but this week if you really don’t need to go then just don’t.
If your extension or entry stamp is after the 20th then just do everyone a favour and avoid immigration.
I have no idea on the policies for all the immigration offices, but you may well find that some will turn you away if you don’t need immediate services.