Thanks Hold I actually remember reading that post at the time, I am starting to wonder if the Devs truly know the answer themselves.
What needs to happen is the Devs start a closed thread explanation to exactly where the soul is determined.
And any changes to that process when new characters are released, put the thread in the summoning souls list of threads and then it will never again be lost and everyone new and old can always return to that piece of info whenever they want.

This will put it beyond question for future and the way players work their souls may well be determined by that explanation.

Except of course what Askora is saying is true, I will hold souls either way due to upcoming soul sacrifice events..