I grew up in 2nd ed and I remember this mechanic well.
Honestly... what are you trying to accomplish here? That's the real question you have to answer. Because 18/76 is the new strength or something? You're only renaming scores above 18 to somethin different than 20, 24 etc...
I mean, there the same room between each integral number: 1.
If you want martial characters to benefit from strenght more, remove their cap of 20.
I'm not sure if you read what I posted, but your general point is well taken. I'm not trying to change anything about the game in particular. My goal was to convert this mechanic into what, to me, it might look like in 5E, given the constraints of this edition and the design space that's left over, so just a bit of idle navel-gazing really.
As to what I think it might accomplish, I think it gives fightery types a little something extra for focusing on Strength, which I've seen some posters complain over the years about them not having, although it really isn't a concern of mine. I'm fine with the way things are and think the fighter and other martial classes get other things that make up for the absence of Exceptional Strength.
It just isn't much of a bonus, so I haven't renamed higher Strength scores, which is exactly what I set out not to do. The reroll bonuses on attacks and checks, for example, amount to +0.475 and +0.9 on average, comfortably within the +1 design space between Strength 18-19 and 20-21. So that's a false claim on your part and why I think you didn't read the actual implementation.
If I was to implement this in one of my games (and I'm not likely to), I think I would either allow the roll at STR 18 or above, and then allow rerolls for a chance at a higher percentile score upon raising the score to 19 or 20, or I would make the prerequisite 20 in the first place to further represent that this is something above the realm of normal human ability.