Not getting paid when clocking in early as allowed by company policy, or staying late to make up time.

So at my company, which is in NYC, we are allowed to clock in 15min early and start working. The thing is we never see this reflected on any of our paychecks. Is this legal/allowed in NYC? Other instances is when we clock in late and have to stay to make up that lost time. We are told that we have to stay 15min after our shift ends and then the clock starts after that to make up that lost time. The excuse is they use Kronos and that’s just how the system is. Is this stuff normal or allowed? We didn’t use to do this until a few months ago.