I have never notice that, (previous days close), I will have to play with it now.

What I do notice has to do with the new day's open. I have found that if there is a large gap, between the open price, and the 4 day moving average, 60 or 70% of the time, the price will move to fill that gap, and test the MA before it reverses and goes back in the direction of the trend. It's seems to be a fractal thing too, so it does not matter what time frame you are looking at.

The exception is if the price opens right at, or just outside the bollinger band. The it will push off of it and follow the trend, rather than fill the gap.

I use this a lot to help me time my exits, rather than entries. It helps me get out much closer to the end of that particular price swing.