While I appreciate the limitations of trying to put a higher powered charger on a car with a small battery like the Volt, you're just plain wrong about the Spark EV.
You may be doing the calculations for overnight home charging. And indeed overnight 3.3kW is fine for a 20kWh battery like in the Spark EV.
But you are selling (leasing) a lot of Spark EVs to people who use and charge the cars at work. These spots are busy charging cars all day and if you have a 3.3kW charger it means your car is perceived as "hogging" the spot because it has to sit there twice as long.
I implore you to put faster chargers on cars which can take them. This will give your cars a better profile among techies. Remember, people are more likely to see and talk about these cars at work than when they are at home hidden in a garage.
And the Spark EV, for example, which can charge at 30+kW using SAE CCS clearly could charge at 6.6kW or more on AC L2 charging too.