Sometimes, we get lucky because of the conditions, too. I've found REALLY deep quarters (as in 12+ plus, measured as "two dollar bills of depth, plus a little" as a direct result of a really good soak on a field, and a whole bunch of years in the ground (nice halo). As you noted though, the signal was super spotty... only reason I dug it, was because I wasn't finding anything, and decided to dig every signal. I believe, as you noted, it was hitting iron a lot, and bouncing around like all get out. This was an ACE350. And with bell tone. Whispers are a matter of volume.
It does happen, but I can't produce it in any regularity. There's also the event where I've found "stacked" items in a hole, where I'll pull one, wave the MD and get another signal... Dig a few inches deeper and out comes another. Then add a third detected only with the pinpointer. End result is greater than 10". Does that make my machine consistent. Nah, it just means I can brag a little about how my machine has FREAKING AMAZING DEPTH.
It's dirt-fishing. When doing ANY type of fishing, human nature is to add a little embellishment.
Heck, you don't even have to be the one doing the detecting! Last week, I was in a park, and a guy came up to me telling me how about in Romania (where he was from), someone using a really CHEAP DETECTOR. He then pointed to my ACE 350 and said "Like that one" (wow. Slap in the face... it's not like it's a Harbor Freight!), and they found and old Roman hoard. I said, "Yes, I've heard of that happening." He then went on to tell me the hoard had a pillar of gold that weight a full 7 TONS. And the guy found it in a cave using his detector.
I just smiled and told him I didn't think I'd get lucky like that in a city park. I've laughed ever since. Cheap detector found 7 tons of gold, apparently waving it at a cave entrance. He might have thrown in that it was done by a 5 year old with a Barbie Detector, and it would have had the same amount of truth.
But hey, it was EXCITING listening to him! I really wanted to detect Romania... and find my own 7 tons of gold!
Skippy