I worked on hydraulic machinery and systems. While standard SHCS exist with 5/32. 5/16, and 5/8 hex sockets. the VERY SLIGHTLY oversize 4, 8, and 16mm hex keys (Allen type)have never failed to fit ... Better. 6 point and 12 point bolt heads are not as small, so the "standard" wrenches or sockets offer less advantage, EXCEPT I'll usually try a 1-1/4" before the designed 32mm. It's technically 0.010" undersize. With my Williams SuperCombo wrenches, I cannot do that; they are made to better tolerances, like the rest of Snap-On products.Grabbing a standard socket to work on an import LOL.
It's interesting to compare "industrial dimensioned" the industrial product lines to the medium duty lines ... while Snap-On SOEXL are among the best products out there, the Williams SuperCombo, made in the same factories, is far superior when maximum torques are needed; less flex, slightly wider jaws and boxes. They also weigh more, and when those features are not needed, automotive, are a disadvantage.
I'm not putting the competition down ... SK, Wright, Proto, and others also make both ... of great quality ... But if you tighten a grade 8 bolt with the SOEXL then the SuperCombo, you will KNOW the difference.