I went to extend my visa exempt today by 30 days at Cheangwattana immigration, they refused to process it there unlike my last 30 days extension (based on a tourist visa). I was abruptly told to do it at IT Square Laksi. I was given this piece of paper which was helpful for the taxi at least. The process itself was fast (around an hour) although it required some extra forms to be filled out on top of the TM7 and copies. Just thought I'd let you all know.
TLDR : Answer Summary
An expat shared their experience extending their visa exempt for 30 days at IT Square Laksi after being redirected from Cheangwattana immigration. The process was quick, taking about an hour, but required additional forms beyond the TM7. A commenter confirmed that IT Square Laksi is the correct location for extending a visa exempt stay, contrasting it with previous experiences of extending a tourist visa at Cheangwattana.