Mezo, In cases like this I usually suggest that you attend a local show and sit in as a test judge and get a feel for how it's actually done.
I also suggest that any competitive bodybuilder who has the potential to compete on the national level, do likewise and sit in as a test judge at a local contest.
Judging a local contest is really not too difficult and the NPC scoring procedure is unquestionably the best way to determine who places where.
Check it out by actually sitting-in and I think you will agree. But just make sure that you can sit in when the score sheets are tabulated. That's where you learn the basics of how it's done.
Judging a national contest is a bit more difficult but the same procedures are used to determine the placings.
I've been around for a while and still find it difficult to place the contestants within an IFBB Pro contest though, but with experience it becomes a bit more simple.