Rotation numbers

[chemist]

I thought they were an industry-wide standard, but at CRIS and The Greek I see

25 Montreal Canadiens
26 Boston Bruins
27 Minnesota Wild
28 Colorado Avalanche

at Pinnacle and Betjm I see

27 Montreal Canadiens
28 Boston Bruins
29 Minnesota Wild
30 Colorado Avalanche

Is this just an aberration or do rotnums often vary between sportsbooks?