With my pup I just went by her appearance. When she was growing fast from about 6-8 months, she was eating as much as 6-7 cups a day, then at 9-10 months that went back down to 4 1/2 cups. Sorry, don't know the weights... But just go by appearance, when she starts look thin or bony, increase the food. When you can't see at least a couple of ribs, decrease.
It's not the size of the dog in the fight, it's the size of the fight in the dog. Mark Twain