I fed my puppy 2 to 2 1/2 cups at 12 wks, then her food intake continued to grow along with her, eventually reaching 7-8 cups a day (and she would have and could have eaten more!) By about 7 months. She started to noticeably slow down at 9 months until she was back to 3-4 cups a day.
The main thing to go by, since all foods are different and activity levels vary, is to just go by the dog. If you don't see at least a couple of ribs qhen they're running, and/or they've lost the taper in the waist when viewed from behind and above, cut back a bit. My dog was always very lean in spite of eating like there was no tomorrow!
It's not the size of the dog in the fight, it's the size of the fight in the dog. Mark Twain