Honestly, it all depends on whom it is you're seeking out.

There are some, to whom you're just a job.
Then there are women, whom enjoy and if you can lock and load numerous times during the allotted date time that you booked. Then unload you shall!!

 
Again, you men can't complain if you're seeking someone who's all about revolving the door.

Assumed that most don't have an issue with multiples if you book 1hr or more.
Sorry you've been having such rough luck :/.  You shouldn't have to book 2hrs or more just to be able to have more than one go.

I took notice of that around 2015/16 timeframe.  My guess is the market shrunk when BP went away, not as much competition.  That's when I got heavy into TER.  Before that timeframe 3 bills/hr would surely get you 2 pops.  Now, not so much.  Worse story happened...once I drove up to D.C. to see a lady I had fantasized about for some time.  Her rate was 4 bills/hr, made it there (3.5 hour drive) got the room number and went up.  She talked my ear off for 25 to 30 mins then a lackluster BBBJ, quickly covered and about 5 mins of actual intercourse before I popped.  Downhill from there as she talked and gave me certain cues that 1 pop was it, then rushed me out.  That being said, MSOG is one of the first things I look for in reviews.  I'm not as young (stamina wise) as I used to be, I just hate feeling ripped off with 30 mins of fluff talk and one pop worth of performance.  

Interesting

I was literally just having this discussion with a friend of mine who is new to the GFE aspect of the industry, she was a FBSM girl. She mentioned that if someone books an hour she does one shot and then a massage for the rest of the time. I explained to her that it may hurt her business. Depending on how long the first shot takes, I absolutely am game for another. Now if the first one takes 45 minutes, that may be pushing it but hopefully you know your body and as you stated the first one took 10 mins, therefore no issue in time for another one.  

Sorry you are having bad luck