New Retrograde Plugin

I'm wondering how robust the New Retrograde plugin really is.
According to the documentation I've seen it should work on one staff - one voice, though I suspect it may do a bit better than that.

However I've not managed to get it to correctly reverse a more complex score.

It ought to be possible for a user to reverse each staff separately, then put them all back together, but I've not managed that yet - after several tries.

I'd really like that to work - though if it doesn't, or is known to be unreliable, I'd also like to know that.