If possible, offer to have your association pick up any price difference. That way you don't come off as ungrateful, or asking for more.
I'm thinking I will probably try to reach out to the organization and voice my concerns, if for no other reason, than to ensure they're not just unaware of the problem /solution.
As far as having my agency pick up the tab for the difference in plates, that'd be ... highly unlikely.
Large metro agency, 1600+ sworn ... Even if it was just a few hundred or less per kit, I doubt they'd do it. Neither will most of the cops. We get $900/yr for a uniform/equipment allowance. Our uniforms are provided, that money is for gear, boots, tailoring, etc.
I've preached for the last four years to guys that will listen, that they can get a solid kit for about half of one years' equipment allowance. Those that were motivated and willing - have already done it. Those that weren't - never will. And they're certainly not going to pay out of pocket to upfit their new hotness free gear.
I'm sticking with my current rig with my (relatively speaking ) heavy plates that stop all known threats. Maybe I'll start saving my pennies and upgrade to a lighter level III plate next year.