Hey!
You are correct, also check these two thread, IZ5RZR - Building of Satnogs rotator V. 3.0.1 - ROTATOR IS DONE! - #12 by iz5rzr , Quartapounds SatNOGS Rotator v3.1 - #56 by remy and the wiki - Heading Calibration.
Do you have any update of your build?