I did a bit of a study of this in relation to PRZ's. What i was hoping for, was a regular correlation with a pattern D point and an extreme murrey line. I looked at it over a week on about 35pairs on M5 to H4 Tfs during the london and first 3 hours of the NY sessions. My findings on the default settings was there was no correlation. sometimes the patterns would reverse at the critical levels but mostly the levels were ignored, so i couldn't include it in my trading arsenal.
There is scope to tweak the settings in the indicators and the methodology does have a healthy following so i assume there is a value in it.