Mine came wired for a third AC and I did add the third AC in place of the kitchen vent. Works great but can only run two at a time. They installed a transfer switch so you can only run two at a time. So I installed an AC with the dump style vent.
On hot days I run the dump AC in the main living area along with the bedroom AC on the ducted system. Once it cools off I shut off the dump AC and turn on the main living area ducted AC and it works great
In south Louisiana in the 90's I am able to maintain 72-73 .
I have also check my line voltages and I am still balanced pretty well
