When I look at Hydroponics Group's page for the kit, it looks like they use some of the tent space for other things (pump, filter, etc.). The actual table size looks like about 2x3'.But i would never think that 180 actual watts could cover a 4x4 thats just crazy talk, maybe as supplemental light but not as a standalone
Maybe they never intended the full tent to be used for growing. At least not "starting out." (I.e., a "starter kit."). I can see how someone might try. I probably would too. But, the site's photos look like only a portion of the tent is used for growing. And, I don't see many complaints (which we'd expect if they were really selling a kit with 10w sq ft.).
Probably poor communication on their part coupled by novice zeal.