Ever notice how you never retrieve S+ and S++ soldiers in the field while Metal Gear Solid V: The Phantom Pain? You may come across some Boasters that appear to have such high stats, but once you're back in motherbase they will always drop down to S Rank or below.
It turns out that, although the game was once supposed to give you those soldiers, they have been disabled from ever spawning in the single player game, forcing you to get involved in online gameplay (and so hopefully spend real money on "MB coins") if you want to see them.
In a practical sense, this unfortunately means that once you reach an average motherbase platform rank of 64, the quality of the soldiers you find in the game will suddenly grind to a near halt.
Consider the following:
With an average motherbase platform level of 58, you have a 15% chance of finding an S Rank soldier in the field. By the time you reach level 64, that's doubled to 30%. This is the sort of progression you see throughout the game with other ranks... but work hard and reach level 98, and you'll STILL have a 30% chance of finding an S Rank soldier in the field!
Once you reach level 64, around the time S+ and S++ should be introduced, soldier rank progression just stops...
Here's the game code in question, with my comments after them showing the average motherbase platform level, so you can see for yourself:
Key: g = E Rank, f = D Rank, e = C Rank, d = B Rank, c = A Rank, b = A+ Rank, a = A++, s = S Rank, sp = S+ Rank, spp = S++ Rank
When you plot the first 100 levels, it looks like this:
And, as had been stated already, you may have notice that S+ and S++ soldiers are never set to never appear...
But what if someone altered the code so that the appearance of S+ and S++ soldiers mimicked the appearance of the other solider ranks, slowly being integrated into the game at a pace that doesn't break the game progression. Maybe like so...
If you think so, here's a simple mod that puts the above code into your game, so you can enjoy the game progress as you reach later levels:
MGSV: TPP S++ Solider Mod (v1.09)
Let me know if you like it!