Small monster spawn behavior

I’m not sure if this is a good place to post this, but,

How does the small monster spawn system work?

I just came back from walking 4km while try to complete “the slay 300 monsters” friend quest while hunting EVERY monster in my area, small and large but I am still being outpaced by a 3 to 1 rate by another hunter.

Am I doing something wrong?
It’s pretty disheartening that I have no chance at being the top contributer because of… ??

the question is how many small monsters did you kill in the 4km walk? are you making the most of that entire distance walked, by killing every small monster in your area, by ensuring you aren’t walking past any small monsters while killing large monsters?
a video recording would be most helpful.