You're probably losing out on the zapping early dimension, as well as the "top post" dimension. Ranking higher on top posts has more to do with who zaps you than how much.

Also, all of the elements are highly non-linear: i.e. being 2nd instead of 3rd is worth much more than being 15th instead of 16th.

If some of these new stackers knocked you down a position or two in each category it could be a real set-back.