I'd imagine that since you already made reduction cuts this year, pruning again might mean a year without blooms. Any that might decide to form anyway could be really small and stunted. The later in the season you make cuts, the weaker the new growth will be at flowering time.
I see a couple of these plants each time I drive into the city that are really full of branches and blooms, but the plants have lost any claim to pleasing form or shape, and the blooms hang down in the dirt on weak stems.
I'd recommend waiting until next early spring to start the next layer of branches.
