Don't know how much you watch any of the MP indicators progress from 0:00 - Aussie session to US session. You'll notice that the upper and/or value lines will expand or contract perpendicularly as well as horizontally to whatever the price movement goes. For my original question I was referring to the perpendicular change. This is a paradigm of using MP as with any coincidental indicator (at least the value lines) go. So for example you don't actually know if you are at the extremes of the price if it has broken out of these barriers (White box in your's). This is more of a trading challenge aspect than it has to do with the indicator. Perfect example is last Wed's move by USD/JPY. Most MP indicators would've been coded to begin to form the upper Value bound at around 111.20 I think. Subsequently it raised to 111.5 levels by the end of that day's sessions as the price went parabolic. So I guess it's the limitation of the indicator. Maybe for FX each session should have it's own dedicated MP structure. I'm sure the charts would look pretty messy unless on say the 5 min.