PCI-5421 16-bit FGEN with "3 digits" of resolution?

[Sparc]

I'm spec'ing some hardware for a client. I need 12k (or more) discrete steps ramped in 500 uS. I find the NI PCI-5421 (100 MS/s, 16-Bit) and am quite happy. Until I read "Amplitude Resolution: 3 digits". I also read somewhere "AC accuracy: 1 mV". WTF?

I called NI and was pointed to this as an answer. I'm not sure what that answer was other than "its a floor wax AND a dessert topping".

So if you any of you guys have experience with this device can you please answer me this simple question:

If I use this device to drive a 0 to 2 V ramp with 12000 steps, will I see 0.00016 V increments in the output waveform? This signal will be driving the control input for a laser while I won't be measuring the output directly, I should be able to detect the change in wavelength with another instrument.

And, if you could answer how 16-bits = 3 digits I'd love to hear that too.

Your help is appreciated,

Sparc