The BS addd-on Nav issues we are experiencing can likely be remedied by adding https://pms50.com/fs2020/gtn750/workingtitle-instruments-gns_fixcompat.zip to your community folder. It already contains the missing line of code mentioned and you don't have to cut and paste your files in the Official folder. It's been published over a year ago is updated commensurate with the WT 430/530 versions. It fixed my TBM and Comanche problem.