“Joseph, cite a source that says that one may daven Shacharit when it is almost time for Mincha”
Avi: Get your facts straight before questioning Reb Yosef. He is referring to a new and relatively contrarian hashkafah among some progressive yungerleit in response to those davening shachris vasikim. It began as a minhag during bein hazmanim to avoid having to make separate trips to the beis medrash for both schachris and mincha. This way they can go directly from birchas hayom at the end of shachris to Ashrei for mincha without missing a beat. Having established this time-saving minhag, it has now become popular even after the beginning of the new zman..