Well, I have no clue of physics, I dropped physics in school with a 5 (in a system from 1 to 6 where 1 is best, and 4 the minimum requirement to pass something), but if I would try to hack through the mailed shoulder of someone, I would use an overhead swing to hit it with the last third of the blade (where the tip is), I would NOT try to hit him with the hilt third.
Besides of this, without any further information (or knowledge about physics) I would say that Xant's/Vibe's graphics a few pages ago are wrong, because the fulcrum is not at the hilt. You swing a sword, it's not jerking off, you don't do it with your wrist! Actually swinging a sword should have several fulcrums, but the most important one should be the elbow or the shoulder. Which already renders the graphics useless.
Could be that I am entirely wrong and should shut the fuck up about matters of physics, but from what I know from reality, and from the simply thought why weapon length was always such an important factor, although you claim that the end does much less damage than the hilt, and the fact that some two handed sword were completely dull at the hilt to give the wielder a better grip (which would mean they make the "best" part of the sword dull to be able to use an inferior part better), I say most kinetic energy is tranferred close to the tip.
Edit: I think the confusion is about certain definitions. I think the worst hits are dealt with the last third of the weapon, but most "pressure" can be given by the hilt third. That's why you try to block hits with this part of the weapon, instead of the tip, because the leverage would work against you. But swinging is a completely different matter, there the leverage works on your side.
I think the "bouncing off" discussion is another important part. If the blade bounces off, it means it delivered all energy directed into the hit direction. But close to the hilt it will not bounce off, but keep pressing against the target, which means it did not deliver its entire energy. Compared to the fact that during a swing there will be more energy in the tip due to leverage, a hit with the tip should do the trick.