The door jamb sticker will always be "correct", but not necessarily the best. They try to get a compromise between ride, handling, mileage, and tire wear, all with one pressure level.
The door jamb sticker on my '95 4WD reads 26 lbs, front and rear. That's as low as I've EVER seen on a door jamb sticker and I run them about 29-30. 26 is just too soft. If you run your tires real soft, your mileage will suffer. If you run your tires really high (like the 45 lbs you have), the mileage will be at its best, but the ride will (should) be very harsh and abrasive. You probably feel every crack in the roadway. Air 'em down to 30 psi and see how you like it.
If you have any doubts, start at the door jamb sticker reading (30 psi in your case) and go from there, either less or more according to your taste.