The issue is actually just that the GenericEntity version doesn't have the owner parameter, which I realised all of 15 seconds after making the report, the error should really reflect that the parameters are wrong and not that function overloading itself is disallowed however.

Can also confirm, measured it semi-accurately and is likely to be exactly 50% sensitivity. Also this effect seems to tied to when you're in any compartment as pilot, cargo, and turret compartment slots all show the same effect in vehicles and in stationary turrets.