Honestly, it's pretty embarrassing, and all on me. I hadn't researched Skype shows at all. The guy gave me an Amazon gift card up front that was worth maybe 45 minutes at my current Skype rates. But due to zero research, I didn't even know what I should have been charging. I agreed that we could just go as long as we wanted, because I trusted that he'd make up the difference if we went over. Turned out, we spent HOURS that night hanging out, watching tv, talking, a bit of the sexy stuff, but mostly naked hangout type activities.
And when the dust settled, he didn't want to pay for anything other than the initial gift card, because most of the time "wasn't about jerking off." Looking back, he probably got at least $600 worth of my time and kept me up nearly all night, knowing that I had to be somewhere in the morning. Was it fun? Yes. Was I dildoing the whole time? No. But it was still my time and should have been compensated (and fwiw, I have had regs since then that pay that much and more for similar types of hangout sessions, so it's not an unreasonable ask.)
I think the only thing needed for me to overcome that sort of issue is to stick to my guns and insist that people play by my rules (which are by no means unusual). I also suggest that models not go off site until they've done their homework and are ready. Learn from other models, and if a custie is trying to tell you how Skype shows are "supposed" to work, be cautious and double check what he says.