also, wouldn't a puppy need more calcium then an adult?
They need the right amount of protein. Calcium promotes bone growth.
Think how fast these large breed dogs grow in such a short time. Think how much they grow in size in the fast year. Specifically in those first 8 months.
Slow and steady bone growth is what you're aiming for with these large breeds. A diet that has too much calcium may speed up the process causing problems with the dog - pano, HD, etc.
Play it safe and feed a kibble that has less calcium than one that is high in calcium. That's just my perspective on the subject.
I've done a fair amount of research an was looking for opinions as the food is listed as an all life stages.
It is an ALS formula, but that's according to AAFCO's standards. AAFCO has a very wide range with what they fine acceptable for dogs.
For the most part you are correct, most ALS formulas are fine for large breed puppies, EXCEPT the one high in calcium. Those ALS should be avoided until the dog is fully grown.