Nice video, thanks.
It's so interesting how much of a difference in general the calorie counts can be - and not just in typical fast food, but even labelled products, as in that video. I think the main thing I've learned from calorie counting is you only know how accurate you are being, when you see results.
Although there is some differences in opinion on how many calories equate to a pound, the most common number I read is around 3500kcal - and that's where we get our 500kcal deficit = 1lbs/week. I've also seen numbers ranging from 2900kcal to 3800kcal. But I know, if over a month/4 weeks, I lose about 4lbs while diligently counting my calories to reach 500kcal under my TDEE, that I've been pretty accurate. If I lose less, I know to adjust what I /think/ is my target calories.
So I think the calories are a guideline, but to really get reliable progress, one has to adjust based on their bodies active feedback (weight loss).