I agree all dogs' needs are different as are the types of foods, and that the pack amounts are only very rough guidelines. The real test is their health and constancy of weight. I tend to feed very few treats and more kibble. The foods I feed are, I hope, good quality but have relatively low protein content. (21-24 %).
I am so grateful my current dog is not a picky eater, but it is hard to limit the food to an always hungry dog!

Thank you every one for all the useful comments, and for your interest.