Wireless radio reception power vs distance
How they modelled the path loss is key to how they came up with 16x the power: -



Slideshow here.

In free space, the exponent is 2 and this means that for 3 times the transmit distance you will need 9x the power.

But, conceivably they could have used an exponent of 2.53 and \$3^{2.53}\$ = 16.1.

Personally I think the marketing guys have messed-up because this is known to happen.