It is not power feeding if the snake accepts the meal. I feed my young ones every 4 to 5 days.
Power feeding is putting the nose of a f/t or pre-killed prey item into the mouth of your snake as it's finishing up swallowing another one so that your snake thinks it's eating one prey item and not two.
Ball pythons know what they can handle. When they've had too much, they'll stop feeding. So, there's no problem feeding a day earlier if he'll eat.