If you ran with 100, you would have a 42% chance of hitting someone with 120, and they would have a 58% chance at hitting you. If you ran with 120, you would have a 50% chance of hitting someone with 120 skill, and they would have the same chance at hitting you. Of course this is all not including any extra mods on the weapons or jewlry.
The real question is how much of that percentage is knocked down once hit by HLD spell off a weapon, or HLA.