Your calories are definitely 10% or less than what they should be. I am not sure if Garmin has determined the cause of the issue. I haven't heard of anybody using older style heart rate straps having the issue, but I can't imagine why a newer strap would cause the problem.

I am intrigued by the BodyBug.
Can you elaborate on how well it functions, and what the calorie prediction was for the 45 mi ride?