Spell rework

currently the difference in strenght and duration between my spells and food makes it problematic to use them together and remain at 10s after the food expires, so I was thinking that the spells could be reworked. Instead of a set duration and strenght we could decide them ourselves and a formula would calculate the ap cost depending on spell lvl rounded to 2 digits after the , . the only trouble I see would be the training for spells and that the strenght increase at multiples of 5 would be harder to implement though that could be balanced with a smoother curve instead...