My up / down scroll bar goes from row 1 to row 65000, so it is highly sensitive to even small movements and is difficult to use. Is it possible to restict its range?
If you press Shift when scrolling the scroll bar, it switches from scrolling the current view area, to scrolling the entire document.
Have you Scroll Lock or something on, which is maybe causing the opposite effect? (Not that I can recreate this on Excel on my PC...)
Have you tried pressing Shift when scrolling - does this help?