See, what I was getting at is if there was some kind of increase to the multiplier of the platinum fairies if used on a platinum unit to go with the plat armor. Plat armor is always 1k base, I know this. Fairies give 2x if same rarity, 1.5x if diff rarity, I know this.
HOWEVER. I was fusing 2 copper heavy armors into my Katie, a gold unit, and was getting a 4x total bonus with two gold fairies in there. Next time I get gold fairies I can screenshot it and show you, or you guys could get in game and look at what I was talking about.

Copper units with two Gold fairies should -not- have been 4x'd, they should have been 2.25x'd, right? But I got 4x exp anyway. The only thing I could think of was that maybe the gold fairies had a bonus due to being the same rarity as the unit they were being fed into.