I believe the loop a head of the indicator is the same as down current mend. I agree with JohnScott it tends to be a softer water technique.
I use it near the end of most drag free drifts twitching the flies slowly as they come off the bottom. It can be simply deadly just before an emergence.
You can also get long drifts on midges when your line is straight down stream from you by letting out a little more line and then tightening up ,letting out a little more line and tightening up...etc. I typically use a midge with a little flash when i use this technique but it is extremely effective when conditions are right.
Sometimes i drift streamers and mend a little harder and more frequently than needed for a drag free drift to give the streamer a little movement . I think of it as a struggling dying minnow. I don't know what the trout think but I do know they like it
All of this said, dead drifting is still the core of most of my presentations.