Nope- It's a technical elision. An 80 kg man in an open field next to a 80 W transmitter is exposed to 1 W/kg, and absorbs microwatts/kg. Ionizing radiation is treated much more rigorously, and thickness and and frontal area are used to calculate the actual dosage, but for EM sources the wattage/kg is not unusual as a metric. It's useful for nearby transmitters, where exposure is focused on a single part of the body, vs simply being exposed to 80 watts of incident power.
> An 80 kg man in an open field next to a 80 W transmitter is exposed to 1 W/kg, and absorbs microwatts/kg.