With every additional account you follow yourself, the incremental contribution of your own follows decrease.
For example, imagine your own absolute UA score is 100, and you follow 100 people, then (damping factors excluded) you contribute 100/100 = 1 to every account's UA that you follow. If you would then follow an additional 100 accounts, so 200 in total, you then contribute 100/200 = 0.5 to every account's UA that you follow.