So anytime a manual gives an exact weight four a counterbalance they are very likely making the assumption you are on level ground and probably not moving. I've never seen a deere manual with specified ballast needed for lifting but the last one I looked at pre-dated DVDs...and cell phones...and personal computers. So between my bad memory and the years maybe it was in there but I don't recall it.
Shoot, millwork? I could probably get in there and wrap myself around a lathe faster than you could stop me. I can see how the same is true for tractors to the "newbs", mater of fact I think it's been proven over and over in news articles and horror stories. I never thought about a class, I already know everything but I even would be interested in taking one, you know, for science. You should send that comment in, I'm sure many dealerships would be glad to have an extra cash flow and manufacturers could make a good show for their insurance folks about how they improve safety.
So as I mentioned to the first question these charts have to assume you're lifting on a level surface, you're lifting straight up, probably not moving. None of that is likely to be true for most applications with a tractor. You'll have a tire in a hole, you'll be facing down hill already trying to lift that fence post out, you're lifting the bale up to to put it in the feeder with two wheels on 12" of accumulated manure. A tractor loader unlike the forklift pushes the weight away from the front wheels as it lifts to a certain height then pulls it back closer maybe even over the front wheels. We also move on tractors a lot while, maybe not ideal or something we should do, but we adjust loads on the move and even pick things up moving (cleaning bales of a field comes to mind). I wouldn't want the liability of saying "ohh yeah, you put 437 lbs on the 3PT and you can lift max load with the FEL safely" vs the forklift which we are 99% safe in assuming the conditions and stability of a lift based on the intended use of the forks (warehouse, lot, off pavement, off road).