that is true for most spammable abilities. Game was designed for skills to fall off as your character progresses so you dont have over9000 skills by level 600. it was also designed to play with controller in mind (mouse support was added much later in development and even now is very buggy) and those tend to have limited button combinations.
Yeah, I didn’t notice you’ve edited your posting and added that part saying that some skills gettin additional hits each level, and that they are calculated separately against monsters def.
Either way, I’m sure lots of numbers and mechanics will change before official release. It’s all a little messy right now.