Maybe tendencies isn't the best word. There are different routes that you can choose to run for the pass option, and different guys you can scheme to become the read key. We might intentionally run different routes from different personnel/formations/area of field/down and distance, but we also maybe don't want to make things too complicated. The good thing about an RPO, like a lot of play action, bootleg, etc. is that there are fewer routes run that are actual options to throw to. A QB doesn't have to go through a progression, so as long as the right pre-snap read is made and option reads made during the play, when and where the ball needs to be delivered is straightforward. But if the defense knows what you're running too, they can jump routes or disguise coverages and blitzes.