[carreau]

While I agree this is marketing stunts in general, sometime the difference between 99.5 and 99.6 reemission is 0.5 vs 0.4 percent absorption. so one way of seeing it the second one is 20% better than the first one at not heating the building.

This is often the case for percentages "close" to 100%, e.g: with LED efficiency, for powerful LEDs the problem is not the quantity of light emitted but dissipating the heat that may need active cooling, so what may look like a few percent improvement is luminosity may actually be a much stronger decrease of the size of active cooling,

Or semi-transparent mirrors in physics, where you really make a difference between 99.95 and 99.96% reflectance, because what you really look at the transmitance.