So I just got this email stating that I should reply by Nov 15th. It's suggesting that Amazon needs to withhold 30% of my ad revenue earnings. I'm a US citizen and I've already provided a W9 so why would there be any withholdings by amazon? No other ad networks do this (at least none that I'm involved with). I have a CPA and am quite capable of calculating / paying any taxes owed. Would like an explanation on this please.