Yah, I really don't think you should be doing that, very dangerous, seriously. You think it's fine for a few charges, or maybe more... but after 4.3volts/cell, the Lithium Ions will be plating on the electrodes, which causes lithium metal build up, and every time you charge past 4.3v/cell you are just adding to the plating, and pretty soon you have a battery that is quite prone to thermal runaway, because of the lithium metal being flammable.

If you could program 4.1v/cell on the Hyperion 720i, I would use it.

Can't wait for A123 to come with their new cells in a couple years, 200C capability, and 350Wh/kg, lipo's are roughly 140Wh/kg.