Have you tried comparing it to Delta 400 instead? The characteristic curves line up nicely, although the speed and grain are different of course.
Delta 400 reaches out to 700nm, which means lighter rendition of reds. So, tonally, I'm wondering if they would look different, especially if there are reds in the scene... a few videos ago, I shot Delta 400 through a 720 filter and got decent IR effects. I couldn't do that with a film that ends at about 660nm.
FP4 might be a closer match...