This is how we do our gaming; each player has their laptop or iPad with them and all sheets are "live", as you say. On evenings when my PC is likely to level up, I have already done the leveling in a copy of the PC and when it's time, I just move any newly acquired gear from the old PC to the new one. I also need to do any long-lasting conditions (STR drain, for example) but our GM has us level up "between missions", so to speak, so we assume we're fully healed when we level up.
This works reasonably well, although the ideal situation would be to find some way to take the changes in the "leveled up" PC and apply them backwards to the original PC, creating a new hero in the process. That way I wouldn't need to move equipment, I wouldn't need to copy conditions or adjustments, and I wouldn't need to change equipped weapons or change prepared spells... I've thought about this a little bit and I don't see any practical way to do it.
For example, when I go from L4 to L5, I've considered running diff on the two XML documents and taking any new stuff from the L5 character to apply to the L4. That should catch skill points spent, stat increases, and so on. The conditions and adjustments wouldn't be in the L5 PC, but if I only
add things to the L4 and don't
subtract them, this would catch most of it. (Hm, I just had an idea about how to do this. I'll have to try it out when I get a chance.

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