Does it even read the assets file for that? The dll for playerspeedmodifier uses constants in the dll, Constants.cPlayerSpeedModifierCrouching. I am not sure the assets overwrite that.
I have ILSpy open on the dlls right now and did a quick search.
If you feel up to trying to mod the dlls, search Assembly-CSharp.dll for Constants.cPlayerSpeedModifierCrouching, and change the value from .04 to 1. ILSpy will decompile it for you, but I've yet to figure out how to recompile. Lol. As I understand, SDX can flip a variable pretty easily for you with a script. But of course it will then be EAC incompatible.