How long do you wait between reps of the same exercise?
This is a very technical question since let Me explain 1 principal.
Rest and pause..
Your routine calls for 3 sets of 10-12 reps and on Your third set You throw on a little more weight than usual, So You give a good 7 reps..Why quit there.. Put the weight back on the rack and rest for 30 second or a minute and than pump out Your last 5 reps.
In reply to Your question once You have fully completed the full motion of the excersise move on to the next rep..
I think we've all studied static holds and other stuff..
Dude do some more reasearch I could type all night long on different bodybuilding philosophies..
Good question though