I'm thinking when the girl lies flat on her back, then more cum ends up on her face especially when her head is positioned so that the guys can shoot all over the face from close range. When she's kneeling in a vertical position, it's harder to get the cum on her face unless the guys can shoot like Peter North, and so a lot less ends up on the face and whatever does quickly runs down unless she's leaning her body backwards and tilts the head back too like Mandy Taylor's position was in AB 24.
By the way, I think Ginger Lynn would be a great choice at her age (42). I've heard women in their 30's and 40's are into nastier fantasies and nastier stuff compared to those in their 20's; I don't know if that's true or not.