Thank you for choosing to use my work,
Hook time warnings will always occur for various reasons that are outside the hands of the developer for server owners.
This is because servers run a huge number of other plugins, lots of which have problems such as conflicts or are doing something inside the same hook as another plugin thus resulting in high/-er hook time warnings because 1 plugin is using the same hook before the other plugin can touch it.
I would advise disabling some of the features inside stackmodifier that you don't need then save config & reload to take affect.
Pls keep in mind as oxide continues to change its hooks either to keep up with Facepunch changes or because it's what they decided to do it also directly affects how the code is handled for us devs/modders which sadly sometimes can directly affect performance.
I don't have / experience hook time warnings in my testing. So I have no real way to monitor those sort of minor affects that can occur for various reasons.
Also, stack modifier in general uses many oxide specific hooks so showing me extremely vague graph data that cannot exactly tell me which hooks are causing those hook time warnings I cannot possibly begin to look into the issue it would be a fruitless attempt..