No, he simply asked why I put the ski on edge to tune the side edges.
He was commenting on the time it takes to change out the diamond stones in my side of beast pro edge guide and then do it all again after flipping the ski around so the other edge is up...his comment was more to the effect of "would it not be more efficient to keep the ski flat so one can work both edges with the same diamond stone and only change out each stone once per ski?".
I understand the pressure issue...not sure I agree, without documentation or evidence, that the tools are actually "designed" specifically to be used with the ski set up on edge but accept that this is fairly standard practice. When I think about it there seems like there would be less chance of the tool rolling and less likely to provide too much pressure to the edges if the side edges are tuned base up instead of edge up. What I like about tuning edge up is that I can see the edge I am working on and if the sidewall is getting in the way and if there are any troubled areas that need specific attention...these things are hard(er) to see on the far edge when the ski is base up.
Also, a note on design...with the ski flat when tuning the side edge wouldn't filed material more likely fall away from the ski and less likely for it to be trapped between the edge guide and the ski where it can cause damage? I know some tools have cutouts to help prevent this from occurring but it appears that there would be less chance of it happening if the base was up when edge filing.