p90 - How do you log it?

I create a new exercise...ie P90X Chest & Back, then fill in the time and cals expended. I class it as cardio because if you class it as strength, it want weights/reps etc...and that changes with each exercise within a workout, and is impossible to track properly. Then when I rotate back through for the 2nd C & B workout, I just adjust the time and cals expended.

I wear a Polar FT40 HRM; (used to wear a FT11 but it finally died)---so I use HRM readout rather than MFP estimates. Just a heads up: when I got the FT40 I was shocked to see what its readout was as compared to the older FT11; seriously 1/2 of calories expended according to FT11 for the same workout. So I wore both at the same time for a few workouts, and the same phenomenon occurred. I queried Polar and they said that the new HRMs are using a more accurate & reliable algorhythm to measure all the data. 500 cal expenditures in the old days of the FT11 read as 250-300ish on the FT40. That is huge, especially if one eats back their exercise calories (I don't as a rule). It is unfortunate that they don't state this throughout the website as it can be quite problematic for users who are tracking calorie expenditure. I don't think this is just a Polar situation, improvements in the methodology goes across brands, hopefully.