The difference is that according to MvGinley you want to take half of the period length and not the whole length when calculating the average. This is because he put more emphasis on the relevancy of newer data compared to old.
The other addition is plotting 2 averages, one based on Close pricing and the other based on Open pricing to create . This can also show when momentum reverses either direction. This is optional, un-check the box in the input settings.