Dew is absolutely correct. However I typically LOVE to hunt in manual sensitivity, for me it seems that I get to hear everything in the ground and run with more of an open iron mask. I have gotten used to some of the falsing that goes along with that, but then again I have the EXII which IMHO discriminates iron better than most. But I have noticed that if I hunt in a high mineral ground area the rig is more stable in Auto Sens than manual, sweep slow and you should be alright. Sure you may dig a few hot rocks but you will also grab the nice finds that others are too impatient to hunt. I have noticed that the "hot rocks" tend to not have that nice silver warble sound as much also. I hunt mainly by sound and rarely look at the screen, although since your using the SE you do have one advantage and that is the pinpoint, try using the target ID in pinpoint mode, "hot rocks" that I have encountered tend to hit at the very extreme top right (where iron hits for me), the SE may see them differently, but you might notice a pattern after digging a few up. Minnesota is full of many areas like this, just ask Chicago Ron, when he has been up this way to visit, he couldn't believe the amount of "hot rocks" here. These same areas have yielded some of my best finds though.
Good luck and HH
Michelob