Finishers for Assistance Lifts

This is what I mean by a finisher, I have seen these in several very strong powerlifters logs like Sam Byrd

http://asp.elitefts.net/qa/training-logs.asp?qid=166393&tid=209

DB shoulder press- 10x75 10x85 8x95 18x55.

Does this add size and increase GPP at a weak point or is there another reason for this.

Yes it increases General Physical Preparedness on a specific part of your body