With the mod active I'm getting an error every ten seconds

ERROR: Missing scale for quality [LuaQualityPrototype: normal (quality)]

It seems to occur each time the script triggers, though the mod still seems to work.

This is corrected by opening the zipped mod and going to control.lua and above "uncommon" put
["normal"] = 1,

the mod does have a slight issue where its not quality right out of the gate, and the stack has to stay in the spawner for a couple of seconds (this is fixed by filtering your inserter to the quality, however it should be quality right out of the gate. I don't know enough lua to fix that one, but there is a work around.