To be be honest grand I think that report would be well out of date nowdays. Let's face it ,it's subjective and was based a lot on houses been rendererd and so your left hand always held the render on the board and useing your right leg etc. To be honest mate I can still plow it on and I suppose if I had a lad mixing I would get more on. We all have good and bad days, You just feel it a little bit more the older you get.
I also think if your a neat plasterer , what I mean is lay your second coat in as neat as you can your not fecking going back to it, to tidy it up and save time. Some Ive seen just plow it on really quick but it looks very untidy and will need more work on it when troweling up, which means more time on a wall.