Gorman on the Pattern of Paul’s Story

I am very much enjoying my first foray into Michael Gorman's, Inhabiting the Cruciform God. One feature of the argumentation in Chapter 1 puzzles me slightly, however.

Gorman argues that Philippians 2.6-11 'is truly Paul's master story' (13). Aside from the problematic use of the term 'master story' and questions about the extent to which any textual unit from a contingent epistle can be said to be as opposed to represent or be an expression of said story, I am interested in the way that Gorman's develops his description of the pattern of this story.

This pattern is identified using the helpful formula: 'Although [x], not [y] but [z]' (16-17). This gives us a helpful way into understanding the dynamic of Phil. 2.6-8. However Gorman wishes to argue for two further points.  First, the concessive use of the participle in Phil. 2.6 also serves to function causally ('although' means at a deeper level 'because'). I agree that this is possible, although it is the determination to read the text theologically in relation to issues of the nature of divine identity that clearly influences any grammatical arguments here. Secondly, however, Gorman states that this pattern or story-line 'appears throughout the Pauline corpus, sometimes explicitly in complete form, sometimes more implicitly and/or abridged' (22). The pattern is, Gorman claims, found in christological, autobiographical and ethical texts i.e. as a way of talking about the pattern of divine identity, apostolic ministry and Christian community. But the examples that he then exegetes are all to do with the apostolic category. This is problematic for 2 reasons: first it lays Gorman open to the argument that Paul's christology is little more than an ideological buttress for his (admittedly counter-cultural) assertion of apostolic power. There is no engagement with those who engage with the rhetoric of a text like Philippians by means of a deep hermeneutics of suspicion (Castelli, Marchal etc.). Secondly, in footnote 60 on p.22 Gorman points to 'two key Christological texts' that echo the pattern of Philippians. These texts are:

2Corinthians 8.9 γινώσκετε γὰρ τὴν χάριν τοῦ κυρίου ἡμῶν Ἰησοῦ Χριστοῦ, ὅτι δι᾿ ὑμᾶς ἐπτώχευσεν πλούσιος ὤν, ἵνα ὑμεῖς τῇ ἐκείνου πτωχείᾳ πλουτήσητε.

2Corinthians 8.9 For you know the generous act of our Lord Jesus Christ, that though he was rich, yet for your sakes he became poor, so that by his poverty you might become rich.
Romans 15.3 καὶ γὰρ ὁ Χριστὸς οὐχ ἑαυτῷ ἤρεσεν, ἀλλὰ καθὼς γέγραπται· οἱ ὀνειδισμοὶ τῶν ὀνειδιζόντων σε ἐπέπεσαν ἐπ᾿ ἐμέ.

Romans 15.3 For Christ did not please himself; but, as it is written, “The insults of those who insult you have fallen on me.”

My puzzle is why, given that 2 Cor. 8.9 lacks the [y] elements and Romans 15.3 lacks the [x] element, Gorman thinks that they are abbreviated versions of the full 'master-story' of Philippians 2.6-8. Why not read Philippians as the expansion of the interchange formula of 2 Cor 8.9? Given the likely background to Philippians 2.6-8, isn't it just as likely that we have in Paul's various christological texts a rendition of the basic theme of the righteous sufferer?