I think that the max you can expect is 3 times on the sim before it gets boring for any one IMC student. The soon reliase that the true worth is limited when they are actually in the plane bouncing about and it after about 3 hours they will understand how the procedures work.
Its a ratio of number of IMC students going through per year against the cost and how many times they will use the sim, suggesting tops £60 per student!!!!