(That's because the charge depleting range is 50 km.)
That electricity is a huge deal, though, and it's completely ignored.
You actually can reverse the real charge sustaining efficiency out of their claimed range figures, though - 50 km on electric only, >500 km on electric plus the diesel, with a 10 liter tank.
That means 10 l/450 km, or 2.2 l/100 km, which is nowhere *NEAR* the target!