Here in the USA, it is INSTANT after the game finishes. Perhaps it's just your location. I have never had a game boxscore not appear immediately after, even at the beginning or end of the season.
Europe is crowded with people, contrary to Americas. Usually in Europe, we have to wait 2 to 4 hours.
Edit:
For league games. Boxscore for Cup Games are quite quick to appear.
Well I guess you'll just have to move here, lol.