You are right, my friend, the guy that is replying your comments is taking the lower bound of the L4 and comparing with the upper bound of L5. Lol. How it works , at least at Google (and is worst at Amazon), is when you get promoted from Ln to Ln+1 , your salary increases just it surpasses the lower bound of the level you were promoted to. I know for a fact of people at Google, L4 that negotiated better TC than what my L5 has. So, but if my L5 jumps ship to Facebook, then he will be easily get a 30% increase, at least.