Log 5 says Bucks home win probability vs. Indiana Pacers is 81%

Basketball.reference.com has the Bucks win probability for tonight's game against the Indiana Pacers at 55%. I think they're way off. They don't explain their methodology, so I can't tell you specifically where they went wrong, but I think they're off by about 26 percentage points.

Here's how I figured that. I took each team's expected winning percentage based upon their home (Bucks) and road (Pacers) efficiency differentials and punched those numbers into Bill James "Log 5" one game winning percentage formula.

The outcome I got was: Milwaukee Bucks (81%) - Indiana Pacers (19%).

Basketball-reference must not properly adjust for home/road because the Pacers expected road winning percentage currently stands at .227, so I don't know how one can say they have a 45% probability of winning in Milwaukee. Maybe they're using some sort of "Milwaukee Yucks" escalator.