My experience exactly.
If I want to sleep all night, I take a whole Advil PM.
Three or four hours, I take a half.
For a two-hour nap, if I really need sleep, I take a quarter.
The stuff works like clockwork...just be sure to have a bite to eat before taking any ibuprofen.
And take ADVIL, not Tylenol.
The latter makes me jumpy, not sleepy.