Yes I know. Like the real RCS numbers etc. But then again do you see manufacturers advertising them ? No.

What would anyone gain from hiding basic performance charecteristics like payload and range ?

Protection of commercial in confidence and national security information.

Being provided full data on an aircraft that say, your potentially hostile next door neighbour operates, would be something of an intelligence coup wouldn’t it?

I know I wouldn’t be all that happy if someone could find out the FULL capability and ‘ins and outs’ of my product just by running a trial and evaluating the aircraft, but deciding not to buy it…