Az1182 hand primes and doesn't use that function on the press, so i wasn't able to test it. When i get the press i am going to try it out and see how i like it.
The powder checker is a die that has a rod in that moves freely. There is a movable rubber o-ring that is a "ruler" that you set, to show where the current powder load youre throwing will line up. While running the press, you watch to make sure the rod and o-ring match on every pull, if not, you either have a too much or too little powder.
While i was adding the powder checker die to my cart, someone in the reviews mentioned the lock out die, which i like even more. Instead of having to watch that o-ring and visually see that its not lined up, the lock out die has an internal mechanism that checks and if it doesnt pass, it wont allow the case in the die and then you have to fix the problem before you can load more. Look up the rcbs lock out die on midwayusa, they have a video on how it works.