Thanks! I learned this technique from an NBA clinician at one of the camps I attended this summer. His reasoning for this was:
1. the lead does not always rotate
2. diving down puts you in better posistion for rebounds
3. better view of contact on the shooter

I've been working on it since getting home & I like/dislike it for different reasons. I guess knowing your partners & teams tendencies would assist in what you should do in this situation.