Exactly, it’s also simply another appeal to a commentary, not giving any real argument as to why we should take that commentary as decisive.
To jump ahead for a minute, it seems to me that there is a far stronger argument to think that the original structure of SN was 47, 49, 51, 48, 50, 46, 45.
Yin Shun bases his entire structure on one attestation of 3 angas at MN122 / MA191 despite, at least in the Pali, 25 of the 26 occurrences of this string are of the 9 anga structure.
However there is a structure, mentioned multiple times in the EBT, across 3 collections and in both languages, i.e;
cattāro satipaṭṭhānā cattāro sammappadhānā cattāro iddhipādā pañcindriyāni pañca balāni satta bojjhaṅgā ariyo aṭṭhaṅgiko maggo
四念處、四正勤、四如意足、五根、五力、七覺支、八支聖道者
the four kinds of mindfulness meditation, the four right efforts, the four bases of psychic power, the five faculties, the five powers, the seven awakening factors, and the noble eightfold path.
it occurs at:
DN16 paralleled at DA2 (adding the 4 jhanas i.e 四念處、四意斷、 四神足、四禪、五根、五力、七覺意、賢聖八道。)
MN104 paralleled at MA196
AN8.19 paralleld at EA42.4 and at MA35 (so if Yin Shun is right about EA we can add Mahasamghika to the Sarvastivada, Dharmagupta and Therevada attestations of the list)
So it is attested in 3 of the 4 agamas in both Pali and Chinese, and by at least 4 different schools of the early 18, just in their agamas alone.)
This is 3 times the evidence than exists for 3 angas at MN122 / MA191
giving us the original S collection and order of:
SN47 on cattāro satipaṭṭhānā
SN49 on cattāro sammappadhānā
SN51 on cattāro iddhipādā
SN48 on pañcindriyāni
SN50 on pañca balāni
SN46 on satta bojjhaṅgā
SN45 on ariyo aṭṭhaṅgiko maggo
This of course dovetails neatly with the idea that the aggregates are a later addition to the EBT, given their just about complete absence from any agama outside S that has them in parallel between languages, as demonstrated at;
https://discourse.suttacentral.net/t/are-khandhas-early-or-late-ebt/
Given the simlar arguments that can be demonstrated for the other “outer” chapters of the prose S, i.e Nidanas and Salayatanas, see here;
https://discourse.suttacentral.net/t/is-the-list-of-the-twelve-nidanas-late
and here;
https://discourse.suttacentral.net/t/are-the-sense-bases-a-late-doctrine/
It seems to me to make much more sense to assume that the original sequenceof SN is that given at DN16, MN104 and AN8.19. at least here we have a list that actually occurs across multiple nikayas, for which thier is not a much more common, muvh longer list (i.e the 9 anga) and which actually does match a substantial part of the SN collection as it is currently grouped, occurring entirely inside the mahavaggasamyutta in a contiguous sequence with only the ordering chaninging, and having the additional benefit of not requiring any appeal to centuries later commentarial materials of either the sarvastivada or the therevada.
I have jumped the gun however and wanted to get to the bottom of how cogent Yin Shuns and Choong Mun Keats alternative is before I mounted my own case, I guess they are both now at least available for comparison.
Metta