I was out hunting early today, and while using the pro I noticed my vdi numbers where a little funny. I was digging quarters and it was at 70-72 and was a zinc penny. This happened 13 times. All were quarters. Not one of them showed a quarter. I ground balanced the unit several different times and nothing at that point seemed to make any difference. I was also using the 5.3 coil on it. Not bad, but I still like it better on the M6. I was in some nice soil, not much trash at all and was in some nice black dirt. Anyone have any ideas?