The best buy list must be wrong, i think you should go with this. ps4 pro outselling ps4 slim just doesn't seem likely.
https://www.bestbuy.com/site/searchpage.jsp?cp=1&searchType=search&st=gaming%20console&_dyncharset=UTF-8&id=pcat17071&type=page&sc=Global&nrp=&sp=-bestsellingsort%20skuidsaas&qp=&list=n&af=true&iht=y&usc=All%20Categories&ks=960&keys=keys