I consider myself to be very intolerant :)
The difference between the spell and action upgrade is that the spell includes new credits, as has already been said. The spell version will remain if you have not purchased one of the credits that it contains. If you accidentially buy the spell after upgrading the action you do get those credits, so you haven't bought the same thing twice...
The difference between the spell and action upgrade is that the spell includes new credits, as has already been said. The spell version will remain if you have not purchased one of the credits that it contains. If you accidentially buy the spell after upgrading the action you do get those credits, so you haven't bought the same thing twice...