The other thing I have also discovered with Imagnesim WSSS Airport Addon is that the product changes the gate's type.
For example Prepar3D default gate type for Gate F40 is 'Heavy' at WSSS.
After installing the addon, the had changed all gates to '‘RAMP MIL Cargo’.
I had advised the Imagine's developer team that 'airport addons should not change the gate’s type'.
There is a reason for that, and it's to prevent the simulator to create its own default ground vehicles, which might interfere with the custom vehicles of the scenery, and generally have a bad fps impact.
Maybe changing them all to MIL Cargo might not a very good idea, we used this method in the past too, but usually used "GA" for non-Cargo gates but that's basically only a label, it doesn't really have any effect on the sim. AI, for example, ignore it, and rely mostly on parking size and airline codes.
However, this MIGHT be a minor annoyance in GSX, because GSX DOES use the parking type, specifically the Cargo/Non-Cargo specification, to choose the operator, so you'll only get Cargo operators at a Cargo parking spots, and non-Cargo operators at non-Cargo parking spots.
That's why you ( or a scenery developer that supplies the airport with a GSX profile ) CAN override the parking type in the customization page. This will only affect GSX, so it won't be confused by placing ( for example ) a FedEx ground vehicle "just" because the parking was set as Cargo to get rid of the default ground traffic.