If we’re on about the same one then I’ve heard the same. The SP figured she was booking guys in 15/30/45 past the hour if she was in 30 minute bookings and texting midway through bookings to say the next was there 
One of the reasons she left.
If it is the agency I think the 10 minute wait whilst they get ready and if you are nearby you see someone leaving. Few years ago a girl I visited complained about the lack of time between guys.
I usually arrive with time to spare and with this agency sometimes gone up early and sometimes a short wait (never significant). Personally doesn't bother me if girls are ready 5-10 after the booking time. Often if girls say they're just finishing getting ready, I say 'don't rush I want you looking your best', as thats what matters to me, but can understand the annoyance to others of having to wait.
My meets with this agency have been from hotels and apartments so would have no idea if theres another punter leaving as they're places people are expected to be. If i'd literally seen another punter walking out the room as I go in, that wouldn't be cool, and definitely not if a booking was ever cut short.. fair enough though, seems i've been lucky with them.
