No I'm not joking, how am I meant to know if actors will stay at the attraction without knowing how successful it'll be? We don't even know if actors will be used at all yet. Even if they are used, we don't know the contract Derren might have with the park, there may not even be a choice to cut down on actors or not.
My point was that you can't compare the use of actors that may be needed to tell the story in a £40million attraction to those used in the queueline at peak times on a rollercoaster.