judge

There are two verses that the western (jacobites) changed for theological reasons.
These are hebrews 2:9 and Acts 20:28.
In the original Aramaic there is not three persons of the trinity. Rather God has three qnoma.
When the Aramaic was translated into greek there was no direct translation of the Aramaic term qnoma and so in time it was eventually argued that there were three persons to the trinity

One can then see why the monophysites, the Syrian Orthodox Church, wanted Hebrews 2:9 to read [i]by the grace of God[i] rather than apart from God.
Like wise they wanted Acts 20:28 to read the blood of God as if the divine could have blood?

The Church of the East retained the original readings, and of course being centred outside the Roman Empire and being independent from the Christological disputes there were under no pressure to conform.
The SOC was however under presuure to have the "correct" definition of the Christ and to reject the so called heresy of the Nestorians. Thus they altered there version of the peshitta.

On top of this there are dialectical differences between the two.

judge

Julian why would the OS come next?

As I previously mentioned we have evidence for the peshitta before we have evidence for the Old Syriac. Thus it seems to make no sense to place the Old Syriac first, don't you agree?