Oops.  I was just about to post this before you posted yours.  I might as well anyways.  -   Furthermore, as far as internal textual evidence goes, there are certain things which clearly show that this could not be the work of Ptolemy.  For example, several of the aphorisms make explicit references to Horary astrology, which is not something that Ptolemy addressed at all in the Tetrabiblos.  One of the reasons for this, among others, is that interrogational astrology (ie. horary) was not developed until the 2nd and 3rd centuries and this development occurred in India within the Hindu tradition. (See Pingree, 1996, pg. 21)  Horary was not a part of the mainstream tradition of Hellenistic astrology from which Ptolemy and his contemporaries were drawing on, and it did not become integrated into the western tradition of horoscopic astrology until the Middle Ages when the various Arab and Persian astrologers undertook a synthesis of the Indian, Persian and Hellenistic traditions.  So you see, even the internal evidence in the text itself with the references to horary show that this could not have been the work of Claudius Ptolemy.