pretty much same here - before i was using a clicker, 450 average portsmouths. now (although there are a lot of other factors here!!) i shoot mid 530s. i recently tried shooting without the clicker and i had a nice vertical line up the target face!!
the first time i shot in competition with a clicker was at the neual (north england university archery league) outdoor champs, in which i won my category by a significant margin.
i did manage to give myself a rotator cuff injury however.
... ergo, clickers are evil