Bay of Plenty vs Auckland -5.5?? Am I missing something?

There hasn't been a lot of Mitre 10 cup posted in here but this one's piqued my interest.

Auckland travel to Rotorua tonight to play Bay of Plenty and they're only giving up -5.5 points. The line started at -8.5 and has shortened in to 5.5 which is never a good sign but I can't figure out why. 

I know the All Blacks are out of both teams but the Bay have been lacklustre this season and I'm from the Bay. 

Auckland have a slightly shorter turnaround and are on the road, but in saying that it's only a three-hour drive down to Rotovegas. 

Aucks last three performances - 

Otago vs Auckland (away) - 6-38
Auckland vs Wellington (home) - 21-39
Auckland vs Manawatu (home) - 50-12

BOP's last three performances

Taranaki vs BOP (away) - 36-29
BOP vs Southland (home/Rotorua) - 17-14
Wellington vs BOP (away) 32-10

Both were handily beaten by Wellington (Auckland putting up slightly more resistance) but other than than Auckland have been clinical against current Ranfurly shield holders Otago and lowly Manwatu while the Bay lost their season opener to Taranaki in a scoreline that flattered them and just scraped passed Southland, a team that'd won only won one game in three years leading up to this season.

There's only one change for Auckland tonight that differs from the Manawatu romp last week while the Bay make three changes to their team including Otere Black, someone Auckland know very well, at 10. 

Weather in the Bay tonight will be perfect, there's a chance of a light drizzle in the afternoon clearing to a clear and still night so that won't be a factor. 

Other than the short turnaround and the three-hour drive south-east I can't fathom why this line is only at 5.5.

With that, my play tonight is - Auckland -5.5 

Who’s is playing auckland mate... no way I will back auk for this game..once auk lost allblack.. they are so weak.. bop home win for me..

yeah I wouldn’t judge the odds on previous  results, BOP on paper look better than this all lack less Auckland team. BOP win outright in my opinion

Awful game, by both sides. Auckland get the win but only cover by 4. Odd's right on the money.