Goenka's vipassana

I can not focus in upper lip: my focus goes in to nostril. I can now watch breath in nostril, but can not stay focussed on upper lip and watch breath. I focus on entire nose and not on upper lip, and watch breath in nasal passage -- is this right ? I doubt is it controlled breathing ? Secondly I want to learn to stay focussed on upper lip and watch breath -- please guide.