Co-Op Weapon Milestones Not Progressing

I've been trying to get 400 Officer Kills, mix of COOP and others, but most kills coming in COOP. I was at 374 Officer kills, played COOP w/ 58 Eliminations, plus a number of assists, but it says I only have 380-some kills now. I have seen this with every other weapon I try to upgrade for every other class - takes A LOT longer because kills in COOP don't count on a 1-1 basis