OK, first, when a detector is giving you icons like "cent, dime, etc." it's dumbing down the info. It's taking a lot of data and averaging it down, making a guess, and you are hoping it's correct. The problem with that is when coins gets deeper or mixed with other targets that guessing often goes completely wrong. This is why we say that you have to give the CTX some learning time. You don't have to carry a clipboard. In time you will know what common targets show as. Also, becuase the CTX isn't averaging the data display, you will see variations. DO NOT expect to see perfect response numbers. An air test of a dime might be 12-44, but in the ground the FE number might be 12, 11, 13, 14 or more. The CO number might be from 42-46. It all depends on the huge number of variables such are ground minerals, EMI, other targets nearby, target position, target corrosion, and others.
Learn to think of zones. Penny-dime zone, quarter zone, indianhead zone, etc. You are brand new to the detector, DIG MORE!!! the more you dig in the beginning, the more you will learn about what the detector is telling you.
Also, do not go use this in heavy iron infested, or super trashy sites for a while. Those are like expert use places. Start out in a simple park, beach or tot-lot. learn the language of the CTX.