Well all things being equal, percarbonate bleach generally out performs perborate bleach at lower wash temps. Perborate bleach needs 140F and above water to really get going, whereas percarbonate will bleach at 120F to 105F, and even in cold water, though contact time may need to be increased.
Perborates were the first "oxygen bleaches", back through the years with detergents like Persil, and Oxydol. However back then it was also common to boil or at least wash whites in very hot water, which is great for borate bleach. As wash temps moved to 120F at (hot), warm, cool and even cold perborate bleach needed something to get and keep it working in the wash cycle, hence bleach activators.
Now if Tide is following Persil/Germany's lead, the perborates will be replaced with percarbonate, and that means no bleach activator. So in theory the replacement of two chemicals with one, should lead to lower costs, but then again perhaps reformulating the detergent had associated costs. Persil powder certianly has not come down in price since they dropped perborate bleach.
Have been trying to find a MSDS for this new "high performace" Tide, but no such luck. Cannot imagine P&G will have both "high performance" and regular TWB on the shelves, as it would imply the later somehow is inferior to the former. Well, at least to moi. Think P&G will roll out the high performance version to replace TWB, thus giving them a way to charge more, if indeed they will as consumers will think it is a totally new product. If consumers found there was no difference between the two detergents as some here have reported in terms of performance, who in their right mind would pay more for the new product?
P&G has always been good at rebranding Tide every so often, to keep the brand "fresh", and up the price, so perhaps this is what is happening with TWB/High Performance