Bluedog,
Ain't buying what you're selling....can't figure out what you believe a swing should be.
12/7/08..you said "back hip fires while hands are going back".
12/23/09....you said "hands and back hip fire together".
You must have had an epiphany between the posts.
You are 100% correct sequencing is important in the swing (or throwing,eating,whatever) so use that knowledge and apply it to the young man's question. Based on the '08 and '09 posts, he might need you to explain your thoughts.
Leverages post...he could be on the right topic but maybe backwards. Timing being late typically produces more pop ups on fastballs than being early ( ask anybody that ever played catcher; it's something catchers look for particularly to opposite field). If he is popping up offspeed, I'll go with Leverage. Would like to know more about the pitching quality, the velocity and what field he hit the flyballs to. Either way, I think the young man may have timing issues as in timing of the stride and heel plant versus "sequencing" of hips and hands....
...unless you want to explain to him how "sequencing" out of whack will affect the swing plane of the bat (it does) and where /how the "sequencing" is breaking down (that is called an answer). Based on his point about hitting the ball on the sweetspot but just under it, your point about "sequencing" may be an issue. "Sequencing" is your baby so the floor is yours...
(the "whip" post...a non answer and essentially self serving. Had you explained (that word again) what causes whip versus the effect of whip you would have made an answer).
But before you do explain, you have to get the 08 and 09 posts figured out. You have alot of good knowledge but often waste it with the "hotdog" answers to high school kids that are asking for help.
You've got it in you...let it out. It would be a shame to die an old man and to never have shared what you know....or do you have a hitting DVD you're selling? "The Zen of Sequencing"?