Well in fairness, that calculator is giving pretty much the same calorie burn as Garmin with HRM gives me for my weight based on the tables.
My n=1 study is that I pretty much used the Garmin figures the whole way through (a substantial) weight loss with diet, and hit the expected weight loss targets based on calories in (using myfitnesspal) and calories out ( including garmin with HRM for running/ outside rides).