Psychic Powers and the Kevatta Sutta (DN 11)

In the Kevatta Sutta (DN 11) , the Buddha seems to categorize "Having been one he becomes many; having been many he becomes one" as a psychic power, which is later seems to denounce "..I feel horrified, humiliated, and disgusted with the miracle of psychic power." Yet, later in the sutta the Buddha classifies the same psychic powers (appearing as many) as miracles of instruction which are praised. Can someone please help me understand this? Many thanks.