My input on this subject would of course not be the same as in the US as our coinage prior to milled coinage was never the same as the quality of say the silver could well give many different readings,as they would often say reduce the content and quality of the silver in our hammered coins,so basically this chart method of TID would not really work for me,as a result of this i rarely look for individual TID targets on the screen,this is the main reason that i use audio mainly rather than rely on the screen which can also sometimes give slightyly false information,but as i see it audio as so much more reliable and also after say about the 7''-8'' mark TID certainly becomes un-reliable.
If my machine give me a non ferrous signal i dig it,the bottom line is that i am using a metal detector and the main target/s that i am after are non ferrous ones,knocking out or notching out certain TID is in my mind asking for trouble ie if i was to not accept say silver foil i would stand a very high possibility of loosing out on very old hammered coins and other artifacts infact anything in the silver range could be knocked out.
Modern coinage in say aprks or tots lots you could do it i guess,i dont have a great amount of problems as such with bear bottle tops or ringpulls as all my sites are very old sites and ring pulls are a modern man made product,of course location does play a big part in this,if you mainly detect in inner cities,parks and play areas then of course you are mostly likely to come across all the modern day trash/rubbish as well.
I tend to run as little discrimination as possible and also try and run the sensitivity as high as possible,and dig everything that gives me a decent signal,a decent set of headphones is ultra important to me as you will have a much better chance of hearing those deep feint signals as usaully these are the best targets,but if i was just using say a el-cheapo set of headphones or rely on just looking at the screen then i could miss many decent targets.
This is of course just my opinion and thoughts on how i detect,the more time i spend refining my detecting techniques ie swing speed and less screen watching my finds increase by a massive amount.