New math
If 80 lbs is the expected weight
80 lbs * 1lbs/16oz = 1280 oz.
1280 oz * 3% = 39 oz or about 5 cups.

We can do this the long way or the short way.
The short way:
the 4 oz the OP is feeding is about 10% of the recommended 40 oz.
So feed your dog ~90% of the recommended amount of kibble.

Jeff, IMO attempting to feed to the expected adult weight is more difficult than feeding 5-10% of current puppy weight. If you feed to the guessed adult weight you would be overfeeding a 8-12 week old puppy and almost under feeding a 5-7 month old puppy. This does depend on the breed and whats going on in the pups life but adult weight is never a given and some pups don't get as big as it seems they will become, others get bigger.

I feed with my eyes and don't care what the scales say. I went with a 6 month old Malinois pup to the vet and weighted him at 31 kg. First reaction of the vet. He's to fat. I told him to look at him and to feel him. After that his final reaction was that he was just fine, not to skinny and not to fat.

Does the dog is to skinny he gets more
Is he to fat he gets less

In general during winter he gets more than during summertime


Greetings

Johan

we can test some numbers. For both of our high recommendation, (your 10% current weight and my 3% prospective weight)
If his dog get 10% of his current weight of 27 lbs. That is 2.7 lbs or 43.2 oz. The numbers I crunched came up with a 40 oz of raw diet.
For the low values (your 5% and my 2%)
2% * 80lbs * 16oz/1lb = 25oz
5% * 27 * 16oz/1lb = 22oz
IMO when dealing with such small differences in a overly generalized guide these can be ignored. I know I do not use a scale to feed my dog.
The orijin feeding guide he is using says 4 cups for for a dog between 65-90lbs(I obtained my 80lb number by taking the mean). At fist glance that looks terribly wrong. The 25lbs difference is an increase of almost 40%. It is important that remember that it is a guide not the tax law. It is also not difficult to imagine a 65lb dog who runs all day verse a 90lb couch potato.
Most vet journals I have read say nutrition and weight is not a linear relationship. Even if appears to be the case in young immature dogs as the dog matures they become more efficient and require proportionally less nutrients.

I forgot the mean
The averages of your estimate and my estimate respectively are 32.6oz and 32.5 with a difference of 0.1oz.
The range of 5%-10% is 21.2 oz
The range of 2%-3% is 15 oz