Gravelly Mountains+ is no different than Gravelly Mountains

Gravelly Mountains+ (or Modified Gravelly Mountains) doesn't have more trees than Gravelly Mountains, even though Wooded Mountains (Mountains+) has more trees than Mountains. This may be intended due to the naming.

To reproduce, use a Gravelly Mountains single biome world, then use a Gravelly Mountains+ single biome world. When using the same seed, they generate the exact same way.