OK guys - if this one is obvious please feel free to blast away at me:

I have a great commute. A third-gear, up-and-over, high-speed mountain road commute. It's 15 miles each way and in third gear the car stays between 3300-4900 rpm the entire way (about 50-70mph). It's HUGE fun and the car does just fine. It doesn't even eat much oil. In fact, if I don't have other long-distance trips between changes I can make it 2.5k miles w/o adding oil.

HOWEVER, I just completed a cannonball-style run down south to see family and over 900 short miles it burned through 1.5 quarts of oil. I spent nearly the entire time bouncing between 85-105+mph, but actual engine speed (in fourth gear this time) was about the same range as my regular daily commute. Keep in mind this kind of consumption is not abnormal for the car - I've been noticing disparity on my high-speed, extended travels since 60k miles or so (currently 94k), but have just now decided to try and figure it out.

So what gives? Is there a correlation between higher actual speed (versus engine speed) and oil consumption? I noticed that I was waaaay deeper into the go pedal on the long trip (at high speeds) than daily when spinning over the hill and I'm thinking that fuel/combustion load might have something to do with it?

Ideas?