In this instance ,it's the data best presented to burnish the image of the FBI as the leading authority on LE technology . Just like their endorsement of .40 (10mm Lite) .
The FBI has its own specific set of criteria for ammunition to meet...which may or may not be what an individual or other law enforcement agency needs. The FBI's decision is not the be all and end all of ammunition...it's simply what they believe best suits the requirements which are a series of compromises...penetration vs expansion vs cost vs performance against auto glass or other obstructions vs controllability vs reliability.
An individual or there law enforcement agency choosing what the FBI uses is not a bad starting point but not necessarily what's best for that individual's specific needs. Just the same as the military...they have their own requirements.