Apologies for posting twice in a day.

I'm currently modeling a building (in eQUEST) and I have run into a
curious condition (counterintuitive). The designed system is a
centrifugal chiller with a cooling tower attachment. The designed KW/Ton
is 0.619, which in EER terms is about 19.3.

However, when I model the same building, but swap out the chiller for a
less efficient (9EER) air cooled chiller, the cooling energy goes way
down (I am still meeting my loads).

The weather file is Atlanta.

So I have a few questions:

1. Is 0.619 just not very efficient for a water cooled chiller?
2. Does it make sense that the cooling tower adds a huge amount of
energy to the building?
3. Is Atlanta's humid climate not a very good place for cooling
towers?
4. Is this simply a case of operator error?

I'd appreciate any input here.
Thanks

Vikram Sami, LEED AP