Most of the suggestions posted are right on target. Here's another possibility, you might have some buildup in your engine which could be affecting your rings, in particular your oil retention ring. Doesn't sound likely since you have been using quality oil...although 10W40 is not the greatest choice unless it is full synthetic because of the number of additives needed for the dino/blend oil to spead the range can cause sludge/buildup--this is well documented (and yes I know it is a blend). This could be compounded with lots of city driving and shorter trips.

There are 2 ways that I know will help correct sludged rings. One is to run a cycle or 2 of using only full synthetic 10W30...preferably Mobil1 as it is very high in detergents. The other is to use your choice of oil at 10W30 and add a quart of Marvel Mystery Oil (the mystery is it is a thinning/cleaning oil) which does very well at cleaning an engine internally of sludge and buildup--particularily at freeing up stuck rings.

Going forward I would change oil choices to either 10W30 if sythblend or conventional or use fully synth for a more spreading range. Although at your mileage and consumption issues, you will probably find using conventional dino oil is your best bet to reduce consumption if the issue isn't buildup.