BogMod/UpgradingCombos

When you see the example of Combos in the corebook and the guy going down 17 xp or whatever and having a completely useless combo it makes me sad. Thats a horrible idea. Thus I propose the following way to make upgraded combos which are really just as much a part of the idea of secret techniques as normal combos are.

A combo with additional charms in it on top of one you have allready made costs you xp for the new charms + 0.5x the cost(round down) of the old charms. That combo needing just that one extra charm costing 7 xp? Not a problem. Huge combo rebuilds will be cheaper to just make a new combo with.