I was shooting at the range next to this "family" Sons and a father.
They were using that target chart, and shooting at it like crap. They were wondering, what was I shooting (A full powered loud .357 8 shot ) so I asked them what he was shooting (story I put on the TFL long before). It was a 1911 US issue 45acp with little or no wear. He gave me the gun after I let him shoot the big 8 shot .357.
I grouped it right off the bat (not my norm) at about 1.5" at 7yrds not including the one 3" flyer.
They and I, was amazed at my shooting.
TBS, It might help at first, maybe.
IMHO, don't let that chart consume you, because it might do more harm than good. "el-natural"
My point is, it didn't help them one bit.