Hello bosbabiesarm...
I live within the confines of Pennslyvania and about 35 miles south east of Pittsburgh, apparently the local books out your way in Ohio do things differently with regard to when they take wagers on games.
Here some locals will take bets the day before a game but most do not take bets until the morning of the game itself.
I have heard that a few offshore sportsbooks offer a "Bookie" option which allows anyone to sign up and have the Sportsbook act as a "Silent partner" by taking all the wagers you enter...for a good piece of the action that is.
About 2 years ago a couple of guys from up around the Allentown Pa area tried to do this on their own by taking all the wagers and then plugging the bets into various offshores sites, this worked.....until they get caught and charged.
I know that no legal Casino/Sportsbooks exist in the state of Ohio because I have relatives that I visit there three or four times a year, thus I would suspect that they are probably using this "Bookie" option that I mentioned.
With regard to the line you say they gave you of Pittsburgh -5.5, that doesn't surprise me at all, year in and year out I wager on as well as against the Steelers and especially when the line is out of whack....when I want to wager against Pittsburgh I use local books because of the same generous lines, when I want to wager on them I use the offshores.
But everywhere is like that, I would imagine that locals in Seattle are only offering Seattle +3.5 right now because of all the local money coming in on them.
By the way, my relatives live on the other side of Youngstown in Niles Ohio, I also have family in Warren, every year the wife and I go to Cincy and Cleveland when Pittsburgh is playing on the road at those Stadiums and my wifes sister and her husband come stay with us when Cleveland is playing in Pittsburgh.
take care and good luck
Jim