Adam, here are some pics of my jab which I purchased from Jene's nursery in Fl in April 2008 as a 7 gallon. Your theory about tip fruting being caused by shade is very plausible in my case as it only gets 5-6 hours of sun in the summer, though it is under lights for 12 hours a day during the winter.
Adam, any guess as to which cultiva/variety this may be
newly purchased in APRIL 08
as it was in June 08
blooming in august 08
fruiting in august 08
my jab today, in the garage for the winter under led light, in middle of huge of leaf push with couple of blooms