Most files will skate at around 57 which is still hard enough to hold a decent edge. I my humble opinion the magical HRC 60 is over rated but it sells!
I agree with you 100% bro, most knife buyers don't have a clue.
First of all my 60HRC may be your 58 HRC or vise versa; most instruments are off + or - 2. I don't even mess with it any more, handheld or portables are only close, they are not dead nuts. I'm not sure if you remember several years ago I asked you what you used because I was getting various readings with mine.
My next door neighbor works for a company that heat treats aviation parts each part they heat treat comes with a specification that has to be dead on. I give her a blade in the morning and that evening she brings it back to me with a certified HRC. And they nice thing; it's free
I like what Kevin Cashen said, HRC is over rated, Test, test and more testing if far more superior than HRC!