That depends on what you mean by 'dial it up', do you mean a throttle? If so then that's illegal. If it is just a 25 kph bike then you can feather the pedals and it will go up to 15 or so and above that you'll have to work for it.

25 kph bike, has a setting for power that has 4 stages and an 5th stage called boost. Would go all the way to 25 with just feathering

Neat, I'll have to try that and see what happens, we have one ordinary e-bike here with a Bosch system as well.