Upon reading this post, I realized I always focused on the tip of the nose rather than the whole body, which may be less effective (for me). I was reminded of my Buddhist college teacher who said that meditation upon the body may cause psychosis or a mental breakdown for some.
Hence, I wonder: Is there any difference between mindfulness of the body (e.g. body scan) and focusing on the breath as it arises all across the body?
My teacher specified he believed focusing on the tip of the nose would avoid any such problems. Is meditation on the breath as it arises across the body a variant or even partial form of body meditation?