How to Override Tessellation Maximum

My mesh does not seem to tessellate beyond a certain point. I can only further increase the resolution by pre-tessellating the base geometry. After some research, I found out that the tessellation is limited to 8 subdivision levels.

I found this source which allows me to change the maximum tessellation, but it appears to be outdated.
The source wants me to modify a usf file where the maximum tessellation variable is stored, but I can only find ush files.

This is still valid and applicable. The file is Flat Tessellation.ush.
Lines to change:

[maxtessfactor(15)]

CompositeTessellationFactors = clamp(
CompositeTessellationFactors, 1, 15 );

Where 15 is should be replaced to your maximum tess value, up to 64