mlb underdog system

I went and backtracked this it seems to come in over 50% every year.

take teams at home that are same division  below 500 pct and bet them when there dogs. 

last year came in at 54 %   and previous year came in at 60%

Example in 2009 when baltimore played tor at home and they were listed as a dog they won all 3 times as a dog.