My calculator says that $13,880 is 330% higher than $4,200 and my long form math says the same thing.

Of course, if you are skimming off profits, and wanting to talk about profits that's another story.

We were not talking about profits, as far as I recall.  We were talking about price rises, and accordingly, as far as I remember we were talking about how much higher $13,880 is from $4,200  - or at least that is what I was describing... and if I wanted to talk about 230% higher than $4,200 that would have lead me to $9,660.  so "technically," what number you use depends upon the topic of the conversation, no?