Because that's the product page you're linked to when you click on their '1000w HID Replacement' button on the homepage.
360+480+360+400+600+400+605+750+600+835+890+840+500+540+735+880+950+880+750+570+525+828+890+810+590+740+590+370+595+585+325+490+365 = 20,628
20,628 / 33 points = 625.0909090909091 PPFD
1000w HPS @ 22" is nearly 1000 PPFD in a 4'x4' reflective space.
So with no uniformity improvements, and 37% lower PPFD, please do explain to me what type of magic this unit is working. Or refuse to listen to science and data because you already spent your money...