i noticed that gas mileage is reduced compared to off mood

 

I'm going to say it probably is, as the Sport mode coerces one to drive more aggressive.

Not only that but it holds lower gears longer and keeps the engine in the higher RPMs, so naturally it will use more fuel, but I think the big culprit is the grin you get on your face and the desire to keep it.

 

Sport mode on 100% of the time. It's now my routine when I get in...start the car, hit the sport button, set PASM to comfort and go.

I just don't like the car shifting to 6th or 7th gear at 30 MPH when not in sport mode. Not only that, it sounds like folks who don't use sport mode often will have higher oil consumption due to the car upshifting and keeping revs so low. I just turned over 3,000 miles and haven't had to add a drop of oil.

 

My Cayenne has around 4400 miles on it now, and just recently has it needed a quart. I broke my in by a 4 day 2200 mile trip the week I got it.

I noticed that those who seem to have to add oil are mostly mild mannered city driving, so maybe the low speed/low gear theory has some truth to it.

Most my miles have been high speed freeway driving trips.

 

During my 4000 miles of European driving,especially on the Autobahn,I did use the sport mode about half the time,with the lowest ride setting
Here in South Florida,I still have it at the lowest ride setting...but rarely use the sport mode..unless I want to race someone on this isolated stretch of road..I find my CT has plenty of power(and I don't even have the GIAC tune yet) and PDCC, PASM and PTV take care of the handling quite well
I have only had to add one quart since i got it

 

at sea level our CTT's are BEASTS! I know this from when I took delivery in TX at 400 feet.
Mile high is a bit different, probably a 20% loss in power, maybe a bit less.

 

Also,my TUBI exhaust(+BMC air filters) seem to function as a sort of "always on"sport mode,by keeping it in a lower gear for longer..and I find myself using the paddles to go up a gear
I have not yet driven it much above sea level,only in the Black Forrest..but those tiny twisty roads did not make me want to see how much power i had less available
Similarly,when I drove out West through Santa-Fe and up to the Start of their ski area(10900 ft) in 09 with my previous CT,I could not tell how much less power I had,cause i was taking it easy..but it seemed more than sufficient(had a GIAC tune)
Looking forward to driving out West again next summer through Colorado,and I am sure it will also be quite up to the task