27 books mentioned in Nestorian tablet (?)

[judge]

So, by the 7th or 8 th Centuries perhaps the 27 Book canon had gotten into most "Nestorian" Churches too.

Well we know that even today COE people use 27 books. It is just that they only regard 22 of them as canonical.
I am not sure that this monument shows that the 27 books were considered canonical, although it does show that, as today, 27 books were read and studied, and revered.

As I mentioned, we do have evidence that early COE churches had a 22 book canon (Aphrahat and the COE liturgy for example). Further we know that today, only 22 books are considered canonical.

What evidence do we have that 27 books were at any time considered canonical as opposed to being revered?

If the other five books were elevated to the status on canon, then who did this, and further who took them out of the canon later on?
Without answers to these questions we seem to be left with no real case that they were ever considered canonical by so called "Nestorians".