Because I don't have enough stuff I'm tracking as it is, I decided after seeing the question come up for about the third time that I've seen, that I will start to track every level of a card in stat gain. With some luck, we'll eventually be able to take these recordings to figure out what formula there can be used in order to determine if a card has been properly fused and mastered without that card either being at level 1, or maxed. Hopefully, a very useful trading tool.
For more depth on this particular subject, see Blynk's Blog
I'm gonna go ahead and start organizing these by rarity level.
Super Special Rare+