In Chaengwattana, 1 floor above the normal immigration division there is the "e-Extension" which is for extending different types of visas including non-exempt visas.
This costs 500 baht extra but can be done online and you only go there to receive your stamp. It's way faster (no queue), way easier (mostly online) and saves a lot of headaches.
At IT Square you are for sure going to need a TM30 (like 99% of the time), at Chaengwattana if you book online and provide all necessary documents there you have the chance to not need the TM30