Whatever logic is being used to check for uncraftable items is reducing my UPS by 10 every 4 seconds.

..crap. I had a feeling that might happen... Alright, well what I was doing was scanning the entire world and logging every reverse factory into a table, then performing the (if not crafting etc) logic on that table, every few seconds. Now that I think about it, is probably incredibly inefficient. I'll try to change it to persistently store the table, instead of recreating it every few seconds. I might still have to scan the world on first load, but that would only be once per save file, instead of constantly

Released an update, should apply to existing saves as well as new ones, and (hopefully) should reduce the effect on UPS. Though I didn't really test and can't tell the difference myself, the removal of the constant 4 second surface scanning should greatly increase performance. I doubt iterating over a tiny table would cause much issue. Hopefully.

Looks like it's been resolved. Thanks!

Glad to hear it!