[ATM] Collimation with a laser

[p.pissias at di.uoa.gr (Peter Pissias)]

Hi,

I recently got a laser collimator and i would
like to ask a few questions.

In collimation articles it is said that the focuser must
form a 90 degree angle with the center line of the tube, and
the primary mirror (and the secondary) must be centered within the tube.

My primary isn't exactly centered within the tube and
i haven't measured the angle of the focuser (it seems 
to be ok but i haven't measured the angle).

With the laser collimator, i have collimated my scope (the 
laser beam, returns to the source).

Is there a possibility that my scope isn't collimated 
because i haven't measured the exact angle of the focuser 
and the primary isn't centered?

Thanks!

Peter