Shock Zapper chain upgrade increases efficiency or not?

[talt]

The shock Zapper lets you choose between 2 upgrades. One chains a second target per zap at the cost of more energy, the other causes stun.
http://orcsmustdie.wikia.com/wiki/Shock_Zapper

I find that the only real limitation on my shock zappers is not rate of fire but charge amount, the fact that chaining extra targets consumes more charge raises the question of efficiency.
Is efficiency increased, decreased, or remains the same?

Efficiency being measured in HP Damage delivered / Charge consumed.
Since the upgrade increases both the denominator and the numerator I cannot tell without specific values (which are not provided).

[xKRS]

I personally like the stun over the increase target. I only use the target if I'm using the zapper only for the fliers. But, if I want to include the zapper in my killbox, I like the stun. The stun also adds a good combo point, which is good for high scoring.

[Shrimp Chips]

Honestly, it doesnt make a huge difference in the grand scheme of things. I suppose its perk is that when you have enemies running through and it is recharging, it can zap 2 enemies instead of one when partially charged. I have not run any tests so I don't know, but I do not believe it makes the trap more or less efficient, just changes the way it hits. The stun is much more useful.

[talt]

It makes a difference because I put put, say, 5 traps and 30 enemies try to run by, end result is 5 enemiues get through and all 5 traps are depleted.
So if I get this upgrade will it end up with 10 enemies getting through and traps are depleted
Or will it kill all of them with a bit of a charge left over on the last.
Or will it kill exactly the same amount of enemies, letting 5 get through.

Any horde large enough to potentially bypass a zap trap due to its firing rate is large enough to bypass it due to having too much aggregate HP for the trap's charge (it will run out of charge). Thus it is ONLY a useful ability IFF it increases efficiency

[Shrimp Chips]

Run a quick test if it is that important to you. Place one up, check how many orcs it killed, then restart and try it again with the upgrade.

However, the lightning trap is not meant to be a trap that slaughters the orc horde. There are better traps to spend with 1000 coin if # of enemies killed per reset is what your looking for. Chain lightning is awesome for bats, groups of hunters, and kobold runners. Stun is awesome for supporting your kill box. But with it's high cost and long reset time, it is one of the most inefficient traps no matter how you look at it. Perhaps it's biggest advantage is one of the few ceiling traps with very long range, making it great for high ceilings where pounders/maces/haymakers cannot reach. However, I will still say chain is not worth it over the stun.