I replaced a head gasket on a 2008 s 60 turbo. Set cams to where the back of the cam was parallel to the deck. Then set the timing marks on the gear to the timing cover. I noticed that in order to rotate the variable timing (gear) clockwise the marks are one tooth off (clockwise). I never loosened the bolts that hold the gear on and would assume nothing has changed from the factory. The bolts are not centered and look like if they were the marks would line up. What is the correct procedure for setting the cams? Why does it appear to be off from the factory settings? Thank You