I watched the video again, trying to decide which frames I liked better, and, generally, I seem to prefer the EI 10 frames because they have more shadow detail and a more pleasing tonality (to my eye). Having said that, I could also see this film being shot at EI 20, especially in a hybrid workflow, with good results. By the way, in my tests, in XTOL stock, I got ISO 15, for what it's worth.
I also compared the P30 against the Lomography Potsdam Kino 100 (I think the consensus is that it is ORWO UN54), and it is a drastically different emulsion, despite also being based on an old motion picture B&W film. Have you had a chance to try the Potsdam Kino 100 or the Berlin 400?