Yes, compass is off by 5~12°, depending on location.
See here:
http://www.ga.gov.au/oracle/cgi/geoA...01&day=1&Ein=D
http://www.magnetic-declination.com/...ne/121955.html
Also, markings on mounts are usually very rough... useful for first approximation only.
Your next step should be drift alignment, and this way you can also calibrate your compass and mount markings for next session(s).