hey,
If possible, that options in the Skill Tree should be disabled.
It looks like the Skill Tree plugin is also modifying other rocket launchers, which normally should not happen.
I will also take another look into my plugin and see what I can adjust or improve on my side regarding this issue.
you can also try loading the plugins in a different order.
For example:
oxide.reload SkillTree
oxide.reload CustomC4RocketTiers
Sometimes the load order can affect how values or hooks are applied and may help to identify or resolve the issue.