Thanks Matt!
My key question was whether there was any evidence that the conditioning method we have been using (1-2% w/w 5-15 min before milling, and immediate dough-in) is better than dry milling (and immediate dough-in) from a low-oxygen perspective.
From the answers, my conclusion is that at best there may be some theoretical but unproven benefits.
It seems clear that other mills, because roll design, diameter, rotation speed, or having an additional roll, can mill grains in a way that provides advantages.
However, for me, I do not see a difference in efficiency, beer is good either way, and if I do not condition, I do not need to monitor the recirculation flow to check whether I am creating a vacuum. The only problem is that with non-conditioning it stops driving a few times, so I need to put the malt back in the bucket and reload, but no big deal, just a minute or two.
Thanks for the offer though