“Net profits” in Hollywood are known as “monkey points.” And monkey points are what the vast majority of Hollywood contracts contain. Only the rarest and most elite participants in any movie receive “gross points” - and even then, there are many different definitions of “gross.”
I have a good friend who is a very well known actor who married a girl from my hometown.
He told me the trick was a percentage of actual ticket sales (not just gross, as it can be manipulated between the distributor and the theaters), plus a percentage of the gross on DVD, iTunes, Netflix, etc.