Looking at: Support
The 450 oz/in is an arbitrary number they chose for the example. They are notating the unit wrong though. It should read 450 oz-in. No division in torque units.
I have no idea what kind of system you're dealing with nor do I know anything about CNC machines for that matter but perhaps you could use a torque wrench to get your figure roughly. There are other ways by they're far more involved.