Doubtful, I'm afraid. HCH-II pilots can "deadband" by taking their foot off the accelerator and then barely tapping it to kill regen, which results in a low-resistance and zero-fuel coast. However, at the root of that coasting ability is the fact that the HCH-II can shut all valves, which effictively allows the engine to freewheel since it is no longer trying to pump air. The Saturn would need that or a similar technology to do the same, and I have seen no evidence of it. Coasting in the Greenline should be just like taking your foot off the accelerator of any conventional automatic transmission vehicle.