An algebraic expression could easily predict the outcome of a set of theories and be relatively accurate. So could a Venn Diagram, and even more so. But I really doubt that he has the education to accomplish that. Here is what I think is happening, hypothetically of course. It's the only thing that makes sense:
If I was, let's say, a bit un-learned or or inexperienced and my detectors weren't selling as well as I would like them to, I could easily make up a chart just like that one. All I have to do is to go to the forums and check the claims people make. Didn't Chamberlain do the same thing? It's real easy to make up a chart like that one. It would take only a few hours to do so, and the law of averages says that I would be fairly accurate on many of the posts, but certainly not all. It certainly is a lot easier than taking hundreds of hours to test them all. 300 detectors is a lot of detector tests, even casually. The problem is though, that he openly ADMITS to not having known how the detectors operate properly, nor how to get the most potential out of them, and more. This protects him from any liable and legal ramifications and it also covers his bunger, because it allows him to plead dumbs - - t.
After deciding to make a bit of it up he he checks the forums for many hours and goes by the claims that Minelabs, Fisher, White's, and Tesoro, etc make. The problem with that is that he suddenly realizes that if he writes down the amazing claims that other brand detectorists make that it will cause him to lose the mark-up that he gets on the Minelabs. The higher the cost, the bigger the mark-up. He has to draw a line somewhere. So, instead of doing that, he elects to live vicariously, but additonally claims that he really just basically turned the machines on, not knowing much about them which he openly admits to, sets the discrimination the best he knew how, and tried them that way. Wrong idea. In fact, he admits to basically only doing that very thing. After he realized that he was being made a fool online, he decides to go back and make a few look a bit more realistic now and then which he hoped people wouldn't notice, which he did. Unfortuneately, many people ARE easily fooled, and most are sometimes, but not all of us at the same time and not always either.
Example #1
A DFX DOES NOT get only 4' on a coin while an SE gets 10 more inches than it. Come on, that is absurd.
Example #2
A Fisher 1270 gets better than 5" on a coin, even a half dime when an Explorer get's (cough, cough, choke choke) 14"! An Explorer II DOES NOT get 10 more inches than a cz-70 either. It even gets an inch LESS when I compare the two here at home. The problem with the charts is that they are for the most part, very misleading and simply sales hype. Is it entirely possible that the bulk of detectorists have as much trouble reading and thinking as he does? I hope not, but NO, many are deceived anyway.
Example #3
A Red Heat getting the same depth as an Ace?
That's even more stupid than the EXPL one!
Example # 4
An Explorer SE or II doesn't even GET 14" in discriminate, in air, unless conditions are IDEAL! What sort of nonsense is that anyway? Does this mean that every Explorer I've ever used is a dud, and that he gets the good ones?
Well, if it isn't true then there is only one thing else that it could be. You all can do the math..
I sent him some of my own results of some of the same detectors he "tested" and he answered that he would expect that a "professional" detectorist like me would get better test results than he was capable of. Professional or beginner, or a space cadet, who cares? I see way too many people blowing their paycheck on some detectors and soon thereafter they go up for sale at 1/3 their initial cost, and only 3 months later.
If he would take the thing off the net it would be a better service to all. Even on here I take everything I read very lightly, but at least I have the intelligence to not make up something like that, which I think he did. Or, maybe, just maybe I just have more scruples.
BTW, yes, a Silver uMax does get incredible depth for it's size, weight, and battery configuration. The general equation for detector power is the amount of power required to run the thing; i.e. how many batteries and how much current, voltage required for operation. This is true of almost anything else electric too, including motors and computers. This is why cheap detectors seldom use more than one little 9v. But I wouldn't make up a chart for this stuff though. That would be stupid. Besides that, if a detector also has a lot of toys and programs to run, the power to the coil gets robbed and consequently so does it's depth too.
He claims 14 inches on a quarter sized coin! NO WAY! But, the test will tell the story. 
