calorie burns

I think I've figured out the whole"mfp calorie burn" issue everyone is always posting about.
I have a hrm that Is the wrist watch kind, I use it when I do cardio. The first time I used it, I was shocked at the crazy burn it showed then I decided to test it.
I did 43 minutes of cardio, tae bo to be exact the other night, I put in every ounce of energy and my hrm showed 488 cals burned, (43 minutes) then I keyed it in to mfp.. what's the odds that the exact number it pulled was 488? I was floored! Couldn't believe it! Any way, I think as long as you are doing whatever cardio your doing 100 percent effort, that when you log, your burns well be dang close (within 10 calories) .. I know mfp is a.data base so it has a listing of max heart rates so that Is applied somewhere in the burn.

Amy way I hope this helps someone...