Did it help sales? IIRC the PS4 slim flopped. And even it it did help sales it was only available for half the month, which means the other half had mediocre August like sales. All the Septembers for PS4 with a new Destiny were superior to it.
Also this article makes it seem like the PS4 was already $299 or similar value. https://arstechnica.com/gaming/2016/09/ps4-slim-review-2/
PS4 dropped to $299 the week before the slim launch.
The price drop/slim helped boost the weekly average over August by 42%. That's bigger than the 2015 boost, +36%.
Won bet with t3mporary_126 - I correctly predicted that the Wii U's LTD at the end of 2014 would be closer to 9 million than 10 million. http://gamrconnect.vgchartz.com/post.php?id=6673287