Questions About Fisher F2 Report Tones

so spent about 3 hours on my first real "hunt" with my new F2,

I went to park that had just hosted several thousand people for the Canada Day longweekend (carnical rides, concert etc) figured it would be a good place for recent "drops". 2 loonies (small dollars), 3 dimes, 7 pennies and a couple of dozen pull tabs and foils (and some other misc including a non magnetic rock that has me baffled)

I dug everything in an attempt to get to know my machine, side note: the ground at the park was hard as a rock, so next trip will be to a beach for some softer digging (i figure more digging = more learning)

observations:

foil showed as iron or foil (near the end of the day I discrim'd iron)

tabs showed as tabs or nickels

pennies showed as zinc or dimes

dimes showed as zinc or dimes

loonies (small dollars) showed as quarters (both the solid nickel and plated steel version)

question is, is this typical? are higher end machines A LOT more accurate?

i realize the LCD display is only a guess, more of concern is if I dont dig "foil" and "tabs" do I risk missing out on gold jewelry? (how do those sound/report on an F2?)