Difficulty Offset = 0 sets the game to a default difficulty value of 1.0 [approx max level 30 dinos]
Difficulty Offset 0.01 = sets the game to the lowest possible difficulty value of 0.5 [ approx max lvl 15 ]
Difficulty Offset 1.0 = Difficulty value of 4.0 [dinos are over lvl 100]
Anything between 0.01 and 1.0 interpolate linearly
The Difficulty Offset doesn't = The Difficulty Level. The setting is a Range from 0 - 1.
If the developers increase the difficulty from 4.0 -> 5.0, then Difficulty Offset of 1.0 will make your server have the maximum possible difficulty level, which in that case would then be 5.0.