If you are doing twice as many sets but half the reps, then you are doing the same volume. But if you are going to be powerlifting by doing lower reps like that, I would not suggest a high number of sets. High volume is better suited to lighter training, unless by chance you are not going to failure on your sets perhaps. Some of the Westside training for example might have you doing 8 sets of tripples, not neccessarily to failure.