Compass correction can I simply twist it?

Hi can anyone help, I am using Apm 2.6 with external hextronik compass it has an arrow on the top casing which i assume to be its front orientation. I have fitted this with the arrow facing forward and have calibrated numerous times and compared it with a regular compass and it appears to be about +35 degrees out i.e looking more north east. Can i just correct this by twisting the compass head so that North on the copter corresponds to north on my compass ?

Many thanks