In my experience there is very little ACTUAL demand for two girl bookings, and would be very cautious of anything your agent tells you.  You do get a lot of callers who SAY that they want it but never book.  Think about it; this is a very expensive service which intimidates most clients.  Hiring one escort is a daunting task, but two?  Come on!  Also, this is not as common a fantasy as most people think.  I've asked my male clients and you'd be surprised at how many are put off by the idea! 

I'm not sure how to put this politely but here goes; not all agents who have "unprofessional" relationships with their escorts are male.  My first agent got me no bookings.  I found out from a reliable client at my second agency that calls were reserved for her "favourites."  These favourites had a way of getting fired when the relationship broke down.  This isn't as crazy as it sounds; these types of relationships are rife in the US stripping scene.   

This agent has already let you down financially. Don't stick around to find out if there's anything more sinister.  Hire a new one and don't be afraid of the male variety.  They can be pretty good at scaring off the baddies.

Oh, and my glasses are totally falling apart.  I am SO scared to get new ones because my current pair are so popular with my clients. 

From what I see, the 'two guys' market are often together in real life and they're charging less than two individuals. Otherwise clients could just book two random men and get exactly the two they want rather than the pair on offer together. Apart from the discount, the advantage from the client's perspective to booking them is that they know they're into each other or at least know they can work together.