Some rests are designed to be shot only cock vane up, others cock vane down. Some dropaways can be used either way. In the case of your NAP rest, it is designed for cock vane DOWN. If you still get vane contact shooting cock vane down, then something is amiss with your setup i.e. nock orientation, rest not dropping soon enough, etc. In your picture it looks like you are even getting contact with the black block that the prongs are mounted to. A dropaway should have no vane contact at all - PERIOD. If it does, then something is not set up correctly.