Slightly off topic but after some email discussion with dev Peter from GraphHopper, I find a more important distinction between BRouter and GH - BRouter routing rules/ costs are heavily determined via a profile script which a user (non-programmer) can modify/ tweak or substitute, whereas GH routing rules/ costs are currently determined solely by the Java code within the packaged APK, meaning a non-programmer can't modify/ tweak or substitute other than choosing one of the 5 Locus profiles (fast/ short car, fast/ short bike, walker). I have found GH favors "dirt track" over "primary road" for a Locus "fast bike" profile however I have no control over this. I'd like to stay on the sealed road if possible. There is no current way to alter this logic, so I revert to using BRouter, even if Compute Instructions are not available.