In my case I don't deal with pros, so I'm the one responsible for coming up with an offer. I can't say the models charge me anything per se.
Personally, I don't use an hourly rate. Due to my lack of experience the duration of sessions varies too much, and they can potentially last too long for this to be a good system for me. I prefer to discuss a fixed base salary with the models and add bonuses later if justified. This depends on the number of models (a solo model gets a little more than what each member of a duo gets), how well the session goes and what exactly we do during the session.
For instance, if a ticklee is extremely ticklish but I see she's doing her best to take as much tickling as she can, I can justify offering a bonus. This is to encourage good "performances". Or I could offer a bonus as an incentive to do a bit more than basic tickling, like the tongue tickling seen in my first vid. After all, not everybody is comfortable doing something like that. But since many people seem to like that kind of activity, paying a bonus can be worth it.
Naturally, since I work with amateur models, the salaries I offer aren't as big as some other companies who work with more experienced models. I also don't have the cool professional settings and equipment some tend to use.
At the moment, the salary I offer a model for a standard session that produces a video of at least 45 minute (after editing) tends to be between....Well, for now, let's just say it's under $500, no matter what the circumstances of the session are.
While I admit it can be an interesting exercise, I don't think we can make any fair comparisons between the salaries offered to models by different companies. There's no standard, and our respective situations are simply too different.