chest fly question

Sup bros,
Right now im doing tempo on my chest (6121)..which if you dont know is really slow movement to keep the chest contracted thru all your reps...my question is...on my last chest exercise which was the pec deck, i was doing really slow movements, but only hitting 5 or 6 reps..keep in mind thats slow movement...my question is should i stay at that weight or lighten up enough to push 8 slow movements? I would just like to hear some of my boys opinions :)

going slow is definately good form but it seems like there would be a line to draw. when u goin quicker or slower ur stimulating fast or slow twitch muscle fibers. i would say move to 8 reps just cause 5 or 6 on that exercise seems low, being that it isnt considered a real mass building exercise