M Philbrook wrote, on Mon, 30 Nov 2015 15:18:19 -0500:

Q1: Since 6.8A times 5VDC is only 34Watts (not 40 Watts), how
can they very clearly label it as a 40Watt device?
Yes, the supply/charger is using a total of 40 watts, some of which
gets lost with in itself the remainder used for the connected devices.
One could say it's 85% efficient.

While the *input* wattage could be 40Watts, given the input voltage
and maximum input current, the *input* is something like 80VA:
https://i.imgur.com/8bl7ypU.jpg

That's 100-240VAC (RMS) times 800mA, which is about 80VA.

If the package wanted to say it was input power, it would have stated
the 40 as 40VA and not 40W, wouldn't it?
https://i.imgur.com/30qxupn.jpg

So it's only about 50% efficient if we believe that the max input power
dissipation is 80VA while the max output power is 40W.

The 40 Watts listed on the package doesn't match either the input
volt-amperes nor the output wattage calculated from the specs off
the device itself.

This description has the same discrepancy:
https://www.touchofmodern.com/sales/.../smart-adapter

I called the company that makes the product but only could speak with
sales who didn't know what the reason for the discrepancy was:
http://listings.findthecompany.com/l...d-in-Edison-NJ
195 Raritan Center Pkwy
Edison, New Jersey 08837-3650
(718) 499-1000
http://www.dglusa.com

So, I'm still left with 40 Watts listed on the package, while no
numbers listed on the device for either input volt-amperes or
output watts is anywhere near that number.