I am trying to get a grasp on differentiating approach notes from target notes in five-part solis voicing.
But definition of target notes seems to include tensions.
Then ambiguity is certainly unavoidable because some non-chord tones belong to approach notes and some others to target notes.
For example, in the picture above, the author of the book says that 2nd lead note, D, is an approach note.
But that is 9, which is a valid tension for C6.
again in the second measure at 2nd downbeat, 'A' appears in the lead voice. And that is the root of A7(b9).
What makes you think that the 'A' in the second measure is an approach note?
Even if a rootless chord is common in five-part solis voicing, ordinary chords with roots are also present.(2nd chord in m.1 has a root, 2nd chord in m.2 has no root)
How can you differentiate chords with roots from those without roots?