I don't think four scenes in a week is a lot at all. Up until a few years ago, the standard for a lot of these brands that would shoot "amateur" girls or new chicks (Team Skeet, Exotic4K, etc) was a three-scene introductory package: when they'd bring the girls in, they'd have them shoot TWO scenes on the first day. Then they come back the next day and shoot a third scene.
But yeah.... they be staying on set all day just cranking out content. You can shoot a few scenes of the chick frolicking around naked, then shoot her masturbating, then grab a handjob scene, a BJ, before she gets to really taking the D. The idea is to just maximize the hours you have her to the fullest extent. Especially when she's new/amateur and she might change her mind by the next day.
Isn't that what happened with Devyn Divine? She was contracted to do 3 scenes but after shooting two, she didn't come back for the third? (Another version of the story says that she shot all 3 but her family found out and intervened to stop the third one before it was released)