Bindings and boots play a BIG role in weight.
An Extreme weighs roughly 4.2 lbs. per ski. An old Chronic weighs about 3.95 lbs. The K2 weighs more because it has the durable 3.5mm steel edges, thicker base material and triaxial braided wood core.
.Are you really telling me about 4.8 ounces is a huge difference? A little meat patty from McDonalds sitting on top of your ski.