Actually, it does charge to full. What people are experiencing is simply that the phone stops charging once it's full instead of continuing a trickle charge to maintain 100% battery.
So if you charge it overnight and leave it on for say 8 hours, the phone will be fully charged after 2 hours and then have 6 hours of just running idle (using round numbers here, of course). That 8% or so drop you see is the phone being on, in idle, for 6 hours. The only software problem is that it takes 10-15 minutes for the battery indicator to catch up and report this correctly.
As for the bump charging, you don't have to turn the phone off, though it is the fastest way to do it. You could also simply wait for the battery to catch up and then plug it back in (with the phone still on) and get the same effect.