This is an EV Grids calculation, not an observation: 330 km at roughly 165 Wh/km needs on the order of 54 kWh of road energy, and the planner keeps a 20% reserve in hand.
A compact (about 40 kWh usable) pack reaches about 195 km before reserve, which puts this leg at about 1 DC session. A mid-size (about 50 kWh usable) pack reaches about 240 km before reserve, which puts this leg at about 1 DC session. A long-range (about 70 kWh usable) pack reaches about 340 km before reserve, so it can usually complete this leg without charging.
Think of 330 km as two halves of roughly 165 km. If you need one stop, it belongs near the midpoint rather than close to either city.
Drive faster, run the air conditioning harder, or load the car and every number above moves the wrong way. Enter your own Wh/km on the planner and it will re-space the stops for NH20 / NH33 accordingly.