Ok, I have this customer that just got the skunk2 stage II cams from me. He also bought the valve springs and retainers. So now he wants to go to stage I cams. He claims that his friend has the same setup and dynoed his car. The dyno showed a loss of power until high RPM. Do you see any reason this might happen? A loss of performance

Please give me your opinion on this matter.
Thanks
jason