people canceling longer WUs

seems if you pay attention to who is pushing what with what after a week or so you get an idea of how people match up. Then all of a sudden without any significant project shifts productions start to become skewed and people who were about tied are now producing 20% more without even clearing their pendings.

TL:DR I think it's noticeable that some people abort longer WUs, with a fixed credit per WU it's not hard to see it. The question for me: is that okay? is it harmful? lots of people mindlessly crunching that don't care, should i take advantage?