OK...if you are hunting on areas that you dont want to damage or dig a big hole, and you asked about pings in the 2-3" range, Ill tell you what I do which may or may not prove to be helpful..
.A good coin size target should be a crisp ping, and if you swing and at the same time raise your coil while rotating 90 degrees, the ping should get smaller and more localized under the sweet spot of the coil...dont look at the screen or even fool with the PP button, just keep your eyes on the ground right where that ping is the crispest. Swing short litlle arcs, almost a wiggle sometimes, as you gently raise and lower your coil...you should be able to stab the target with a screwdriver if its a coin in the top 3" easily...now if its a crisp ping and you start your rotation while raising your coil and the ping is still hard and crisp when your coil is a foot off the grass, its a large deep can or something, and you wont get it with the screwdriver...also I lower my sens (about half power) this seems to help in keeping the ping targets small...it takes just a little practice a few months of dedication...heck, you can practice in your own yard with a coin laying on the ground or pushed down a few inches....this method should put you within a golfball size area of where the coin is, which means you should be able to stab it with a screwdriver in a few attempts...then you just wow out a little hole, stick your finger down in there, tip the coin on edge, and pull it up with the shaft of the screwdriver and your finger working together.
If you get some time and practice you are gonna see what everything is telling you...we still get "fooled" though, which is what makes this sport so surprising...lets say you get a tight nickle or even a Dime signal in the top 3"...you pretty much have gotten good at stabbing coins, but for some reason, you cant stab this "coin" no matter what you do...that when its a RING, and not a coin! So you can slow down and use the pinpointer.
You just gotta get more time on your machine and keep analyzing all these weird events like you are doing and asking why? You are gonna be alright if you keep reasoning like you are doing, and trying to figure it out...plenty good members here to help shorten the learning curve for you.

Anyway, this screwdriver trick is a good one learn, it really helps a fellow get on target fast, even if you have to dig, at least you are right on target to begin with..
Mud