Francis Waston on the Longer Ending of Mark as an 'Authentic Pastiche' Which is 'Appropriate to the Gospel of Mark Itself.'

In a previous post I mentioned Larry Hurtado's apparently inconsistency - arguing that the reference to Secret Mark in the Mar Saba letter is a forgery in part because it appears as a 'pastiche' while accepting the long ending of Mark as an ancient addition to Mark made up of the three other synoptic gospels.  Now it is time to look at the apparent contradiction in Francis Watson's estimation of the same material.  Francis Watson, perhaps the critic most associated with the "Markan pastiche = modern forgery" argument goes even further than Hurtado and not only accepts the longer ending of Mark as an ancient edition to Mark but moreover as an ending to Mark which is 'entirely appropriate' to the gospel (even Hurtado and Evans don't go that far).  Let's start with a typical reference to the longer ending in one of Watson's books:

It is for this reason that the two disciples on the way to Emmaus are represented as not recognizing the traveller who joined them on the road - not because he appeared to them 'in another form' (en hetera morphe), as the longer ending of Mark claims in an attempt to summarize the Lucan narrative (Mark 16.12), but because the conditions were not yet in place within which faith becomes a possibility [Text Church and World p. 290] 

Yet when we look to his statement in his Text and Truth we see Watson argue that even though the longer ending of Mark was made up of other synoptic material it is still should not be rejected by modern textual critics:

My own argument shows that, at least at certain points, the Longer Ending is appropriate to the Gospel of Mark itself [p. 90] 

But that's very curious given the lengths to which Watson argues that the pastiche nature of the addition to chapter 10 of Mark in to Theodore is by its very nature proof of forgery.

As I have to attend a children's birthday part I will simply cite from Roger Viklund's summary of the development of this argument in scholarship.  Viklund notes:

I shall focus upon another old argument which Raymond E. Brown dealt with already in the 1970s and since then has been recycled by many, for instance by Per Beskow. As Watson explains it: “It has often been suggested that Clement’s excerpts from the Secret Gospel are a mere mosaic or collage, drawing from mainly Markan phraseology to create a new narrative loosely related to the Lazarus story.” While R. E. Brown seems to have taken this to indicate an ancient pastiche forgery, Watson must believe that Morton Smith cut and pasted from mainly the Gospel of Mark in order to create the first Secret Mark passage within the Clement letter. Watson continues: “The Secret Gospel passages comprise 14 sense-units (phrases or sentences) distributed evenly throughout the pericope. The Markan and other synoptic parallels have contributed 66 of its 157 words, in sequences of between three and ten words. A minimum of 32 of the remaining words are employed to complete the sense-units in question. That leaves just five sentences out of account, which tell of Jesus’ departure to the tomb; the voice heard from the tomb; Jesus’ entry into the tomb and his stretching out his hand; the departure to the young man’s home; and the night spent together. These sentences are full of synoptic language, but they are not dependent on synoptic word-sequences. … The pericope would seem to be the work of an author determined to pattern his own work on mainly Markan phraseology.” 

Some might argue that it is entirely possible that the letter to Theodore is an ancient or even modern forgery. Yet the fact the fact that the addition referenced therein is a pastiche cannot possibly be argued to be a proof in any sense that the material is forged. Indeed I am curious when the pastiche nature of the long ending was first recognized in scholarship. Was it before or after 1958?