HPS - Sterilizing Tunnel


I´m a recent validation tech. on a Pharmaceutical company. Recently me and my collegues preform a qualification on a Sterillizing Tunnel. This tunnel is quite different from what we are used to. The tunnel belt only runs at the time that the vials go inside the infeed zone. In another words the tunnel belt runs and stops depending on the vials that go inside. Another problem is that the measurment of the belt speed, is only upgraded minute after minute on the tunnel operating panel.
After we preform our HPS, we verify that the velocity measurment on the YOKOGAWA register was having peaks and is dificult to determine a constant velocity and therefore to determine the velocity for production. Does anyone ever validate a tunnel of this kind? Can anybody give us a help? The tunnel is a Bausch+Strobel DHT3670