Guys, guys, GUYS...........please........enough with the over-complicated theories. It's really simple - you need to grind more than 5 secs for the purge to be effective and flush your machine a touch longer. Not referring to you D., but in general what people think a grinder retains and what it actually retains are different. The purge is not always 100% effective (stuff gets clogged on the sides and all sorts of places) and the duration of a purge varies depending upon many factors such as grinder design, how clean it is (the grinder), the types of beans/ground and relative temp+humidity - yes, it's scientific........or you can just do it simply by testing each morning how long you need to run it so that shots are the same (or similar). As a person who has to do your same routine more than a dozen times a day, 6 or 7 days a week, depending upon what grinder I am doing a purge on, I can run up to 50g through it before I am happy. I will let you in on a big secret.........it's impossible to get them to be precisely identical without wasting a lot of coffee.
