I've made my homework this afternoon and the only bass where the OC-5 tracks down to the low B (0) is my Le Fay Remington Steele. With the others (except the EUB 6, as expected), it can track down the low B, but has a tendency to glitch below the D on longer sustained notes as noted by @Al Krow, but strangely not on the E string.
That said, as it's glitch-bubbling like an OC-2, that's great.
And I love the Poly mode too as I can almost emulate an old Hammond B3. It's just missing the background noise and Leslie, but it's great sounding for some Indian music à la Trilok Gurtu with Jonas Hellborg.
I'm glad that you like it too @Kev, and as you noticed it's a terrific OC-2 on its own, with way better tracking.
It's also on my (small) pedalboard.