The current system was developed by Colonel Dave Harbour, who was a famous turkey hunter and outdoor writer back in the 70's and 80's. He tried to set it up so that the weight, beard, and spurs were all basically equal, and it does a pretty good job of that. The NWTF adopted his system and it remains the same today, except that they now reduce all scoring to 16ths (1/16 of a pound being an ounce of weight, and 1/16 of an inch being the most common small fraction on a tape measure). In decimal conversion, 1/16 = .0625.
Back in the late 80's I noticed that heavy 2-year old toms could outscore smaller, but longer-spurred toms, so I started "tweaking" The Colonel's system a bit. I didn't think the 3 categories should be equal...my contention was that body weight should mean substantially less than the other two, and spurs should bear the most important influence of all three. After all, a big Osceola only weighs about 2/3 of what an average eastern does, or even less, while some of those little 'ole swamp dwellers sport daggers for spurs. I've personally killed several Osceolas with spurs longer than 1-5/16, but weighing less than 14 pounds! I believe Lance Vincent's world record Osceola was the first tom with recorded 2 inch spurs, and it held the top spot for several years, but when big Easterns (30+ pounds) started showing up in the record books with equally long spurs, there was no way an Osceola would ever regain that top spot! I wanted a way to better level the playing field between the different subspecies, while rewarding gobblers who lived long and grew hooked spurs.
In my system, I gave weight it's true value (1 pound = 1 point, or .0625 per ounce), but the beard gets 4.0 points per inch (.25 points per 1/16th inch), and the spurs get 32 points per inch (2.0 points per 1/16th inch). Thus, a gobbler weighing 20 lbs., and having a 10 inch beard and matching 1 inch spurs would score 124 points (20.0 + 40.0 + 32.0 + 32.0 = 124.0). With this system, it is very hard for heavy toms to outscore long-spurred gobblers, and that's exactly the way it should be.
A complete side benefit was that the scores then come close to equalizing "trophy-class" gobblers with "trophy-class" whitetail deer, which is something most hunters can relate to. The example entry-level "book" tom above that scores 124.0 points would be approximately equivalent to an entry-level "book" trophy-class whitetail scoreing 125.0. The current world record turkey was taken by James Lewis, and it weighed 33 lbs., 9 ounces, had a beard of 13-3/4 inches, and spurs of 2-1/4 inches and 2-1/8 inches. Converted to decimal numbers and added together in my system, this tom scores 228.5625 points (33.5625 + 55.0 + 72.0 + 68.0 = 228.5625). In Boone & Crockett, their world record typical whitetail scores 213-5/8 points, so you can see how close these systems are to one another.
I wrote the NWTF years ago and they considered changing their system, but the "ship had already sailed" by then, and it would've been too big a headache to revamp their records. Oh, well.....