Well it seems to be tracking fine but my Bassline only has a two octave range - the acid test ( ahem, no pun intended !

) will be when I get the Dark Time - 5 octave range - but I don't forsee a problem :
Here's what Moog tech support emailed me in this regard -
The Old School's pitch CV input is usually a bit higher or lower than 1 volt/octave. If you can adjust the CV output on your synth/sequencer, you may be able to dial in the appropriate range there. That would be the easiest solution.
I think you are referring to CP-251, not VX-351. There is attenuator on this device that will allow you to dial in the appropriate CV range. It will be handy for doing lots of modular stuff. Actually, you can increase CVs by going into the mult, coming out twice (thus doubling the voltage) and then attenuating down to the desired range.
The bit about the the VX-351 vs CP-251 still has me a bit confused ( I 'd mentioned using a VX-351 attenuator in my email to Moog tech support ) - I have both units anyway, so I'm using the CP's attenuator- I haven't tried the VX's one to acheive the same result, but tbh I dont see why it wouldn't work ? Perhaps some of the more experienced guys on here can shed some light ?
Anyhow, certainly with a CP-251 you can get the right amount of voltage to the OS's pitch input by either attenuating down or doubling & then trimming down as described above, so happy days !
Finally from Moog :
A third option involves soldering a trimmer in series with resistor onto the OS Analog pcb. It should only be done by skilled, experienced technicians
I decided against this as it will cause warranty issues of course & my OS is only a month old.