I was using Fluke 117 to measure the frequency (Voltage measurements seem dead-on, but no idea how accurate the frequency measurements really are).
DC offset on the generator seems to work, and adjusting it doesn't have any effect on the Hz measurement shown on multi-meter.
Meter seems to measure "AC" from the signal ok, so that would point to DC offset being close to 0V when its set to 0 on the generator.
I'll see if I can get this hooked up to a scope, that should show what is going on.