Correct Score Lines 0-0

[trueblue2]

Hi.
Why is there such a big discrepancy in the odds of 0-0 between Oddswizard and the Bookies ? The Betfair markets seem pretty efficient so is this discrepancy an error in the program ?

For example, the Premiership this weekend :

Liverpool v Stoke Oddswizard : 18.2 Betfair 12.0
Arsenal v Villa Oddswizard : 26.5 Betfair 18.5
Norwich v Everton Oddswizard 19.2 Betfair 11.5
Sunderland v Fulham Oddswizard 18.7 Betfair 10.5
W Brom v Southampton Odddswizard 21.6 Betfair 12.0
W Ham v Cardiff Oddswizard 20.6 Betfair 12.5
Swansea v Man U Oddswizard 23.1 Betfair 12.5
Palace v Spurs Oddswizard 21.9 Betfair 13.0
Chelsea v Hull Oddswizard 26.3 Betfair 20.0
Man C v Newcastle Oddswizard 26.4 Betfair 17.5

[Alex]

Strip profit margin ~20% from the fair odds generated by OW and you will get close figures.