If the arrival is on a Saturday morning, i’d have to wait till Monday to be able to report to the immigration for TM30. Would that mean exceeding 24 hours and hence, being fined?

Logically, no, because immigrations office are closed on weekend. Ask by phone to be sure. For safety i went directly to the police station when they started to be  stricter about it (It' written on the paper you can do it there in cas no immigration office or if they are closed). Had to be the main police station of the district and the policeman there  was more piss off than me because nothing was computerized so he had to write it down on his lob book. It was few years ago.

They will not fine you for going on Monday if you arrived at your residence on a weekend or holiday,

They will not fine you for going on Monday if you arrived at your residence on a weekend or holiday,

Great, Thanks!

Logically, no, because immigrations office are closed on weekend. Ask by phone to be sure. For safety i went directly to the police station when they started to be  stricter about it (It' written on the paper you can do it there in cas no immigration office or if they are closed). Had to be the main police station of the district and the policeman there  was more piss off than me because nothing was computerized so he had to write it down on his lob book. It was few years ago.

Thank you

OP, I have always been confused about this. Are you returning to a residence you live at in Thailand after some trip away? Why is tm30 required at some imm offices and not others? 

OP, I have always been confused about this. Are you returning to a residence you live at in Thailand after some trip away? Why is tm30 required at some imm offices and not others? 

I think by law it is required. The degree to which it is enforced varies, i guess