I would suspect that the set point on the silver puppy is set too low. Unless both the expensive distiller and the distilled water you purchased are both defective. with out a conductivity meter exactly like one of these, you can't be 100% sure.
The idea is to remove all the conductive minerals and other contaminants from the water. I use a simple $100 distiller similar to the one below. It works perfectly and it takes over 3 hours most of the time.