VA: Draining less than I expect (in General)

I know if an enemy dies, any damage done over their HP doesn't drain or do GA back at me. But check this out, the guy lived 2 rounds, so he clearly had enough HP:

Destiny lacerated Maqufas [1753]
Destiny draws strength from his weapon! [154]
Maqufas's Guardian Angel smote Destiny (96)

Destiny eviscerated Maqufas [1857]
Destiny draws strength from his weapon! [64]
Maqufas's Guardian Angel smote Destiny (83)

Normally I seem to drain about 8%-10%. The 2nd one there is weaker since I guess he had around 900 HP left.

My VA level is just over 2000. Wiki says that at max you'll get 40% drain, and to keep VA at the same level as the damage you are doing. Since my VA level is higher than my damage, and the guy clearly had enough hit points in the first round above, why did I only drain a bit less than 10% instead of more?

They didn't cast dispel magic on me.

This is Unstoppable Force vs Onitin.

Another fight. Unstoppable Force vs Excrutiator. He has no dispel magic or anything like that. Doing the same 9% or so life drain as before.

Destiny lacerated Assassin [2222]
Destiny draws strength from his weapon! [195]
Destiny burns from the flames surrounding Assassin (13)

Destiny dislimbed Assassin [2208]
Destiny draws strength from his weapon! [46]
Destiny burns from the flames surrounding Assassin (17)

R.I.P. Assassin

Clearly in first round he has 2222 HP so I'm getting the most drain I can. My VA is at level 2066.

So when wiki says:

VA has reduced effect when its level is low relative to the damage done.
You should keep your Vampiric Aura level equal to the level of Damage you inflict for maximum result.
Maximum effect would be 40% Life Leaching, or very near it.

What am I not understanding? I thought with 2Kish damage and 2Kish VA I'd heal around 350-400.

the max amount you can possibly drain with VA is not necessarily the same amount as the optimum amount : )

you CAN train massive amounts of VA in order to get the best possble drain, but keeping it around you MPB is much more efficient.

Ok so long-term I should plan on about 10% drain if I level it the same speed my damage goes up? That's kinda annoying, I was hoping to use it to counter GA since GA almost never does more than 40% damage back at me. Then I could even dump DM. :)

Coupled with my morg I have seen 60% leech.

TMDoc

I have enchanter (Vila Raviojla) with Vampiric Aura: 105,100 (?). My tank (Kraljevic Marko) is doing all the damage and he gets about 30-35% leech.
VA drains a lot, but You can't expect much when Your level is only around 2K.

Hmm ok. How much damage do you do vs the 100K VA level?

his Most Powerful Blow: 26,803

I did some experimenting a long time ago with VA. Turns out there are a couple of things interesting about it. VA seems to become less effective the less HP an enemy minion has. It is also not as effective against ToE. VA seems to be more effective the closer a hit lands, damage wise, to the actual level of the VA. If you hit for 100k regularly, VA would work most effective if you took exactly 100k off your opponent, they had no ToE, and had HP at least equal to the damage dealt. You can have a 100M NW weapon and 100M VA, but if you hit an enchanter with 20 HP you are going to draw only a fraction of that 20 HP, which I believe is capped at 40%. Therefore a VA + MH of 60% is maximum I believe.