Strictly speaking, this is not the correct method for torquing down a head.

According to the manual :

1. use a little oil on the underside of the bolt heads and a bit on the threads
2. torque to 45-50 Nm
3. tighten a further 180 degrees
4. check that when a torque of 110Nm is applied that none of the bolts move

There are variations of the "correct" method above, but the most important thing with fitting a cometic gasket is that the head needs to be flat (ie skimmed), as does the block (which isn't good enough if it hasn't been decked).