The _level suffix in the name seems to have been given to abilities that show up on the pages of General and class/path abilities you can select from when leveling up a character. Check for the Xpos and Ypos tags which denote where on the page they show up. What page they show up on (general or path) is determined by its prereq tags. If it doesn't have any, but has x and y positions defined, it just shows up on the general page.

Note that the x and y coordinates start with 0 and go to 7 before they wrap to the next line down, at least on the default screens. Anything below y 5 will require you to scroll down, but it does support it.