Yes, it is unreasonable to expect a second pop on the shallow end of remaining time. The way I see it, if you need more than half of whatever time agreed upon to get the first pop, then the second one isn't likely to come within the original time window.
Exceptions to this would be if you're barely over, say, 35 minutes into an hour, the first pop comes. After a 10-min breather, a 15 min pop could happen, maybe.
In a 30-min session, I wouldn't expect a second pop attempt, unless maybe if one could pop in the first 5 minutes. I once popped in 3 minutes (yeah, the pussy was THAT good).
The problem I've run into more than I care to mention is the lack of interest in attempting a second pop, regardless of the time remaining. 20 minutes into an hour session and one pop happens, you shouldn't be getting dressed shortly thereafter. What the hell is this! Who 'quits' after 20 minutes of an hour's work, and you want to get paid for the whole hour. THAT'S BULLSHIT, ladies!
If the guy concedes that he doesn't think he achieve a second pop, that's one thing. But for you to be ready pack up and go with a huge amount of time remaining, that's just straight up bullshit.
Or, Maybe he's testing you. "Oh, i don't know if I can get another one," the guy says
Maybe he wants you to try.
![Wink2](images/smilies/modern/wink2.gif)
Maybe he wants you to prove how badass of a hottie you are to get him to achieve something he didn't think he could. But, if you want to take the easy road and quit after 20 minutes....