HELP my bike says one thing but mfp says another

puddintot

I have an exercise bike that you work your arms as well as your legs. I keep track of time and speed but when I add it to my diary on here the calories burnt are different than the bike says. Does mfp take weight into consideration? Would that even matter? Totally new to this idea and would love input please. Not just log the lowest number because then I feel cheated.