I thought the diagram by NVFOA_Ump was excellent and a great visual to explain the BBW concept... nice job!!!
This concept is simply about whether the player being blocked low had a chance to see the block coming and a chance to defend against it... 10 to 2 is that visual area. 2:00:01 to 9:59:59 is not that visual area and is a foul... it is black and white. A line is drawn in the sand, which is all we can ask for.
Now the challenge is: Can we tell time? The tough block is 2-to-3 and 9-to-10. 4-to-8 would be a clip and shouldn't be any more difficult to call than in the past.
Go back and look at some low block situations from previous seasons and see where they fit into this rule now. We've found some BBW fouls called that are now legal and obviously some 3 & 9 blocks that are now fouls. This is an "adjustment change" for us but it sure beats the adjustments and confusion we were having with the former rule.