Hi Beekay,
probably you confuse failure point with target of DRPO. Those part of text that you've posted - it tells about conditions of DRPO failure, i.e. if price exceeds 0.618 retracement by close.
And target, yes, 50% support/resistance of thrust of DRPO (although this is not specified in book). In book minimum target is OP (AB=CD) from the tops of DRPO. I give you example on Gold chart, although this DRPO is not perfect:
Sive please i want to ask if you think gold will reach that DRPO target considering the bounce from 1728 area. Thanks always.