I hunted an 1872 country church last spring and after about an hour of hunting I had found nothing. Most all the signals were single digit iron hits, so I wrote it off as hunted out. Today I decided to hunt it a second time around and concentrate on any double digit signals that were 40's and above. I walked at a slow pace and when I hit a target that had VDI readings in the 40's and 50's I stopped and swiftly swung the coil over the target several times. On the hits that were coins or bits of copper the numbers would average up by fast swinging the coil over the target. The Wheats and the Indian Head first hit in the upper 40's to very low 50's . After swinging over them at a fast clip the numbers would average up to the mid to upper 50's. The Seated Dime gave a more normal 74 VDI soft whisper and when I increased the coil swing speed it then bounced up to a very decent 84 VDI reading and would come back down to the low 70's when I slowed down. After digging the plug it was very elusive but I finally found it with the pin pointer at about 8 inches. Fisher does mention this technique of sweep speed under the heading "CHECKING A TARGET" on page 30 of the manual. I was somewhat surprised that the VDI would sometimes average up as much as 10 digits with this technique...Thanks for looking