In the process of making black powder do u have to go through all 3 stages in a row?

im talking about the ball mill method from pyrocreations.com. I dont have 11 straight hours i can dedicate to making it. can i do the 3 hour stage one day and the other stages other days?In the process of making black powder do u have to go through all 3 stages in a row?
You can certainly let the ball milled powder sit in the ball mill over night and do the rest of the steps the next day.