No. Unfortunately, it's not that simple. Pull tabs and some bottle caps and a fair bit of other junk will show on ferrous 12. BUT most of the time, it will give you lots of other clues to tell you that it is junk. It will take some time to learn the clues but once you will, you will be able to skip over bottle caps and most of other junk with ease. Mind you, just like with many other machines, whatever you skip, you will never know for sure what it was BUT after a month of using CTX, whenever I called bottle cap, I dug out... a bottle cap or similar piece of scrap.
Accurate? Most of the time, Yes. Still, I did dug out several silver pieces when I called a copper penny. Got a piece of pipe when I thought I was digging silver...
Indecision... you will face a lot of it. You can never be sure unless you dig it out, not even with CTX BUT once you learn the CTX, your confidence level with soar up.
Most potential users are intimidated by the multitude of possible settings. Don't be! Just don't try to use every option at once to start with. Start easy, with the factory presets. Modify progressively as you learn the machine. Heck; my wife (I love her a lot but she is not a techno wizard nor experienced detectorist) normally pinpoints for me but sometimes, she grabs the machine when I'm digging out a target and than she often puts me to shame by locating good targets with ease because (I think) she is not over-thinking it! When she calls "it sounds good", most of the time, it is worth digging!