10 hours isnt that quick. 
I have had full correction using a pro polish (nothing fancy) on a rotary on a Peugeot 206 in under four hours.
The Merc AMG I did a while ago took about 9 hours to get full correction on the paint. 
Just depends on the car and whether its paint is willing to work with you. At the same time. 
The last BMW I did took over 14 hours to get full correction. 
Mike