Not sure about the US, but for UK accounts as soon as you receive more than 4,500 GBP worth of payments they automatically require you revalidate the account "for EU anti money laundering requirements" and upgrade you from personal to premier / business (depending on how you answer the questions).
If you're serious about business you need a premier account. Twice on these forums I've gone to the trouble to buy something and the seller hasn't been able to accept the payment because they have a standard account which doesn't accept payments from my cc feed, only if I have the funds in pp which I didn't - their loss.
Offcourse yes, and we don't just pay it to them... they deduct it themselves na, as a fee of the service they provide!