Okay - you mean the feature that you could use as long as you did'nt use your hardware pedal to control sustain?
It's only on/ off now yes. I don't know when it was removed, or if it's intended it's not there anymore. In Wurlitzer V you could set from 0.00-100.00%, and then get a fixed sustain (on/off) period for each played note. But it only worked until you used your hardware sustain pedal. I don't know if it responded to a hardware expression pedal to set the value. The feature could be of some usage.
The feature is in Stage-73 V. So it could be a bug, that it's not in Wurli V2.