Its an apples to oranges comparison. The power ranking apply to tournament selections different in the two sports you are desperately trying to compare. The RPI for hockey is an accurate indicator of who is going to make the NCAA tournament with the exception of any teams outside the top 16 who win their conference tournament.
FU has an RPI ranking in the 30s but if they didn't win the Summit tournament, no chance they were getting an at large bid.
Also, I haven't read too many posts on here by anyone saying UND is a better hockey team than St. Cloud.