The disclaimer on the bottom states that due to the change, it is hard to show on the charts. Basically, leeches are STILL generated in the 1-50% range, but then they are multiplied by a factorr of their swing speed. That is why you will never see a dagger with 100% life leech, but commonly see lances with 100%. This is ALSO affected by the generated SSI.
I have posted a decent (still confusing) chart and explanation in the
Item FAQ