I usually use the time at the very end of the session, or withhold XP calculations to give out at the begining of the next game. As you have noted (and alluded to earlier), I already deviate from the RAW in terms of giving out 1/2 XP, but I am using 3.0, and unless I misunderstood it (which is, obviously, possible) I believe that table uses average character level in the party, which is what I understand APL to mean.
If I am mistaken, then that sounds like a good thing. I mean, what you describe sounds even more tortuous.
In any event, the RAW XP rules don't help me with these goals:
(2) Slower rate of advancement, particularly at higher levels. Under a flat XP system, higher level characters still gain something for fighting weaker opponents, so the world doesn't have to suddenly become filled with Epic monsters just because the PCs level up.