The description of hold mode and driving in sport with a depleted battery isn't quite right. Hold mode should be considered a charge sustaining mode which just runs to engine to keep the battery at a certain level of charge. When the battery is depleted it really isn't - there's still 20-30% charge left in the batter (I'm sure someone will post a more exact number) and it just charge sustains the battery to that level. Sport mode is just a remapping of the accelerator so pressing about halfway down is like flooring it. If you floor it in Normal, it should perform the same. In sport mode it is harder to get smooth slow starts, but it is possible with careful feathering of the accelerator. It's all just software settings giving you different vehicular dynamics.