Two rounds in an hour? Depends on the SP—some’ll let you double-dip if you’re slick and speedy, but check the rulebook unless you want a mid-session “so, we bangin’ again or what?” clown moment
Yes, or near the beginning of the session if you're too shy to ask when booking. It lets the escort plan. Though 2 SOG in the hour is pretty common. Less time than that and it's more rare.
It is common but always check before hand. There have been some ladies reviewed who only allow one shot and try to get you off as soon as possible. So doing research on the lady you want to see also helps.