MapMyRun - Watch app Vs phone app

I normally use the MapMyRun phone app, but today I used the watch app on my Samsung gear 3.

A half hour brisk walk using the phone app usually comes in at around 200-280kcal. Using the watch app today a 45 minute brisk walk came in at 561kcal.

Has anyone else had this sort of discrepancy, or does anyone know of a way to rectify it? I've tried the usual uninstall/reinstall tricks, but I'm doubtful they'll make a difference.