OK, I've had the AT GOLD for a good while now and have always used the All Metal mode with the Sens. set at MAX. With this setting the threshold is very erratic. but I get max depth. To get the threshold smooth I have to turn the Sens. down about 3 or 4 notches and I feel I'm loosing depth, but in the Disc. 1 mode and Sens Maxed out the threshold is smooth. Any thoughts on this.