Moving Average of Only One Day of a the Week for Metastock

The following MetaStock formula is for a moving average of the Friday of every week, if you want it calculated on any other day you would substitute a 1 for Monday, 2 for Tuesday, 3 for Wednesday, and 4 for Thursday. The number of day you wanted would replace the two 5’s already in the formula. This moving average is currently a 6 week or 6 Friday moving average. If you wanted to change it to another periodicity you would change the 30 to the number of weeks or specific days multiplied by 5. In other words if you wanted a 4 day moving average of Friday you would change the 30 to 4*5 or 20.