realskiers

I don't have any experience with the Salomon bindings.? I would certainly follow up with Salomon before just accepting it, especially if it is off that much.? Hard to believe your powder skiing would not have been affected by being 3" forward.? What was the nature of the horrible day.? Too far forward should have resulted in the tail of the ski washing out (not holding).? If this was your first day in these skis on hard snow, maybe it is just getting used to the skis (don't know your level or experience or anything).

Were your friends on the same skis and bindings?? There are differences among ski manufacturers; in general the "austrian" skis will be farther back than yours (the so-called French style).

General information is that it should be OK to just move the bindings on the track if you have that much room, but 3" is a long way to have been forward.? Most flat skis have a mark on the ski that is supposed to line up with the mid-sole marker on the boot.? If the mark is on the ski and visible then stick the boots in the bindings and see how they line up.?

Alternate. There are excellent articles on Peter's website that talk about mounting the binding such that the ball of the foot is over the "center of the running surface".? You might check that out as well; many of us adjust our rail based bindings by that criteria on hard snow (some move back a bit for softer snow).