The #10 has a profile,the 0 is straight and too much fueling for most sane drivers.
The #10 has a nice bottom end profile that is smooth coming on with a little defuel on top to control EGT's without power loss, the zero is fuel fuel(rack travel) when ever your up on boost.
Note, my race pump doesn't even have a zero in it, makes it too un-driveable and it's not needed.
Jim