I just got one last week and my bike mechanic guy (who uses one too) set it up for me, but it has been completely wrong on the calories burned; for a two-hour ride today it said I burned 1300 calories. It said almost 4500 for a century ride last weekend, also not accurate. It also gave me a reading for my heart rate info today, but I didn't have the heart rate monitor hooked up! Anyone know why it would be doing these things and how to fix?