[rwcarlsen]

It's not really overloading. it is associative:

    2*time.Hour+1*time.second == time.Second+time.Hour*2

[wtallis]

I believe that's illustrating commutativity, not associativity.

[thaumasiotes]

The illustration is wrong, but the claim is correct; multiplication between units and scalars is just as associative as you'd expect. Multiplying one kilowatt by an hour gives you exactly the same result as multiplying 1 by a kilowatt-hour.