I don't know if you understand "standards" but if all of he helmets are designed to pass CPSC then they are all equally protective within the limits of that standard. As it turns out, foam is pretty much the same density and hence it is extremely difficult to increase the protection of a helmet if you are using foamed plastic. If you have two helmets and one is heavier than the other and they both pass the standard than all that means is that the cheaper one is built with less quality control. Larger and more vents requires a lot more care with the foam in order to retain the same standard. Now, you could, for instance, use a less dense foam which would allow more compression which in turn would reduce the maximum acceleration with a head blow, but unfortunately people will only put up with a helmet of a certain limited size so you cannot use any significant less dense foam since it would require a larger helmet with more, less dense foam.

I forgot that they now call that "wavecell" when I bought mine they called it "q-cell". They also make a high end version that includes that IRS or whatever it is called that allows the helmet to rotate within limits on your head in a crash. Their testing showed no improvement since the wavecell reduces the impact to the point that your neck is not really threatened. Like I say, there is insufficient data on whether the wavecell makes any difference but if they are at least trying to use real science then I am willing to believe them.