Calorie Count on Polar S-720

HarryS

I am using the S-720 polar with power option on my bike. In order to track and graph my indooor trainer workouts seperately from those cycling outdoors I created a new Sport called Trainer as it has default sports for running swimming & cycling only. When I import my exersise data from the watch into the software, all values transfer fine including the calorie count estimated by the heart rate monitor. The moment I change the exersize in the daily diary entry from cycling to trainer, the calorie count drops by about 40%. When I toggle back to cycling it does not change back however. What's going on here? I have no idea where the software takes these values and how it recalculates to some other calory value. The value reported by the heart rate monitor is about 20% under what the power meter suggests. The changed value is less than 50% of that. Any thoughs? Thanks in advance.