Me too i get less vote per post even if i have more and more followers. I am not really sure why but I think with HF 19 we can vote less often (10 votes per day at 100% vote power), maybe steemians also vote too often for themselves and less for others with the x4 rewards on comments vote.
I think steemit team should cap the number of comments vote at 3 per day at 100% vote power.