Oil consumption with 6.6 turbo Duramax??

I have a 2011 HD2500 and I change twice a yr. need it or not and never over 5000 miles. I also drain overnight and you could get up to an extra quart out. I find extremely hard to check the level as the dipstick drags oil up the dipstick tube. If you drain overnight I find will hold 10.5 US quarts. I also found always appears overfilled unless checked the following morning and after a long drive. The only time I found mine used any oil was pulling a 15,ooo lb. trailer in a snowstorm in 4 inches of snow in 4 wheel drive at 45 miles an hour when you just couldn't safely get in a high enough gear to keep the RPM where you would like it. Otherwise uses none and I use Rotella T CJ4. I doubt you have a problem these aren't oil burners.