Average voltage (pwm regulated) out of motor voltage range?
Motors have so many "characteristics" the boilerplate values are very vague. 

Min voltage is usually required to get it going. 

Max voltage is the max you should apply to a starting or locked rotor motor to keep it from burning out. (Though the latter is not always true.)

However, that's just the numbers they have to give you. They are almost always based on the simple "Apply voltage and go" control model.

The truth is, when properly controlled you can use MUCH larger and smaller voltages assuming...


You do not apply a voltage large enough to break through the insulation and or arc out.
You do not supply enough current to demagnetize or magnetize the motor or burn out any internal wires or insulation.
You do not overheat the motor.


Having said that, Over-rating a motor will void it's warranty, and may significantly decrease the life of the motor. The latter is especially true with brushed motors.

In your particular application the max you can ever supply to the motor is 12V which is well inside the motor rating so you are good to go.