Using the 1 less club was simply used to be sure you got it over the lip, not the distance issue. If you are within the green, then yes, you normally have to take 1 or 2 more clubs (4I or 5I instead of the 6I). I was assuming you were playing a long bunker that was not reachable to the green. And choaking up a little helps counter the fact that your feet sink into the sand a little while the ball rests high on it.

Congratualtions on the great 9I! Always nice to get applause from another group.