Why not positional variation?

[oshfdk]

Intending to answer to the thread question I found this, started to read the "hypothesis", already stopped again at her very first table and was reminded why I don't give much about existing "researchs".
She claims that there is no y at a middle position.
...

No, that's not what the paper says. The conditions under which that table was created are stated explicitly.

I have never seen an a at a starting position in whole script.

Folio 1r, the very first line of the manuscript: