How do the promotions work for Wildwood Crest?

Wildwood Crest - How do the promotions work for Wildwood Crest? As far as I know, there are some conflicts with seniority. If a man/woman graduates the police academy before another man/woman, he/she should be ahead of him on promotions, correct? These departments might not think the "outsiders" see this, but trust me, we do. Totally unfair to the men who have been on the streets longer than others, especially the ones who earn it. Shouldn't there be an IA done for these men/women?