I honestly need to check how often I add oil in my '02. I have Amsoil, bypass oil filter system, and changed oil about 30K miles. Oil analysis was still good, but my instincts made me change out. I did have to add som ocassionally, but I'm a type A that has to keep the oil fil at the top of the mark. Iop of the head, there are a lot of ways these motors "use" oil. Evaporate out where the blow=by bottle is (was on mine) and through the cylinders and out the tail pipe. I get a little blue smake at startup, so some might by seeping past the valvetrain. I wouldn't be too worried.
What kind of driving do you do? I have a mix of city during week, some highway on the weekend.
Curious to see other responses.
Wiredawg