Pre-season predictions are nearly never right; pre-season predictions that try to ballpark points are even less so. No one can predict the future. No one knows what players will get injured and when, or how a goaltender will play, or if some outside problems will strike a club. The best hockey pundits can do is either depend on the law of averages or guestimate based on where a team finished the previous season.
But what about trades? What about off-season unknowns? How do you compare what basically is tantamount to two different teams across two different seasons playing against basically totally different squads?