I've run across a situation at the beach the other day where I realized that I could have easily missed smaller gold items.
One of the other detectorists found a tiny gold toe ring at the beach, and he was nice enough to let me try ringing it up on my machine to see what it looked and sounded like. To my surprise I got no VDI, and only the smallest peep of a low tone close to a nickel sound. A few tries and i got a brief 12-08 one time. It was something I would have easily dismissed as trash.
What I determined is that because I was using the salt water setting to deal with the black sand I was also filtering out the small low signals. Sure, I got all the high tones easily enough, and found dimes at a foot deep, but the gold ring at the surface would have been a total missed find.
I think this would also apply to the E-Track as well as it works on the same principle. But the lesson learned here is to not use the salt water setting unless there is no other alternative for the conditions. Since I've turned off the setting I found I still get good depth, and get more falsify and more small foul like trash, but I'm more confident that I won't miss the gold either.