Well this is good reading. Did not SRAM claim that the new Red was something like 1770g? Obviously that was lie.
I wonder how mucch Veloce and Centaur really weigh?
Well there are Lies, Damn Lies and Statistics
You can bet they did certain things but they wouldn't outright lie, which would be illegal
165mm Compact cranks
Lightest BB configuration
Took the lightest individual components from a sample group
I am sure there are other things as well.
Campy on the other hand may need to comply with some Euro standards on claims, so it could be random sample, average of samples, median, most popular configuration (ie 170mm 53/39 with 12-25)
Shimano most likely have their own way as well