Number (Primitive) Curiosity

I was helping a friend in their GH studies and came across this occurrence I can’t explain. As you can see in the attached GH file, when the Num collector is placed between the list and the find similar component, there’s a bit of a deviation between the two.

I rarely use the components in the Primitives because I thought they were just placeholders. Is there something more to them? I also noticed that the speed of the instance with the Num collector is much faster (relatively speaking) than without.
Num (65.1 KB)