what people seem to forget is that these "giant" breeds grow much slower then an average sized dog. feeding 5 cups of food at one sitting is far to much food to put into the stomach. do a little research on bloating and you'll understand why. with these "giant" breeds several smaller meals through out the day is the general recommendation. these dogs can grow well past 2 years of age, the important thing is to provide high quality foods, high in protein. ~and also lets not forget that although these dogs are heavy boned, they're going to have to keep carrying that 100+ lbs into their geriatric years, not every bully is meant to weigh in at 140lbs. a slim athletic build is not always a bad thing.
92 lbs at 7months is over weight you should cut the food back. Don't be in a rush to make him big this will cause problums for him in the future if they are over weight. Keep your bullmastiff on a diet and he will be health and will most likely live longer.
Be sure to check out his lineage if that information is available to you. If he came from a sire and bitch who were both large examples of the breed, his being 92lbs may be normal for that blood line-for example one of our Bullies was easily 80lbs at 9mo and is very healthy now at 2 yrs, with no growing pains. Some breeders may say to cut back on the food, but it sounds as though your Bully is active enough to handle the recommended amount food your brand suggests, just be sure to break feeding down to twice a day and not all at once.
I have a bullmastiff named Hunter that is 7 months old, and even at birth he was larger than all his siblings. At 7 weeks old he was 17.5 lbs when we got him. He is held to a strict diet of his SD large breed puppy low-calcium diet at recommended or less servings. He gets his SD dental treats and no table scraps allowed. He was just weighed for his heartguard and advantix, and weighs in at an athletic 109lbs. He is not fat, the vet thinks he is in excellent shape. There are good basics to work with, but some dogs are genetically larger and grow faster. If your dog looks too thin, then increase his amount of food. If he looks heavy, with little or no definition...give him less food and more exercise. If he/she looks athletic and well defined, they are most likely getting the right balance of food and exercise. Remember to avoid heavy stress to the dogs joints as he grows. Joint supplements if you can afford the little bit extra also help as well. Large breed dogs are known to grow "irregular". So a base line is a good place to start, but keep in mind each dog is different and will have to use some personal discretion in deciding where your dog is at in relation to the base line. Good luck.
I have a 6 month male bull mastiff that weighs 90 pounds.