The fee pays for her time, counted from the moment she reaches your door, and for her company through every minute of it. That is all it pays for: time and companionship only, as the footer of every page on this site repeats.
Her cab within Zones 1 and 2 is folded in, and so is the work of the desk, from the first reply through the check to the message saying she is on her way. Nothing is sold by the item and nothing appears on arrival; there is no service charge, hotel supplement or late-night premium tucked away anywhere.