I have always been fan of AU-58 coins simply because they (usually) have much better eye appeal than, say, an MS 60-62 coin. And they can be had for less money. It's a win-win.
But I had no idea TPG's sometimes will assign the coin an MS grade when, in fact, the coin has wear. Is this common practice for all four top-tear graders?
Direct quotes taken from the PCGS grading guide -
" If you need magnification to see the 'wear', it is either not wear or it is wear that is so slight as to not prevent the coin from grading Uncirculated."
" Thus, what appears to be wear is sometimes incomplete striking, bag/roll friction, album slide lines, cabinet friction, flip rub, slight mishandling, or actual wear from slight circulation. The grades involved are AU58 and higher. This element of grading is not just about the difference in AU58 and MS60, since there is slight wear or friction in grades up to MS67."