There is something a bit messed up about that blog post.
Siau says that his 10 feet of his 11 AWG cable has a return resistance of 0.0252 Ω. If you look up the
resistance/foot of 11 AWG copper cable and multiply by 20 feet (for the return resistance), you indeed get 0.0252 Ω.
But he says that the same length of 12 AWG cable has a return resistance of 0.04 Ω,
1.6 times larger than his 11 AWG cable. From the same table, the return resistance of a 10 foot length of 12 AWG copper cable is 0.0318 Ω. Only 1.26 times larger than his 11 AWG cable. For the purposes of his discussion, this is not a small correction! Maybe, in citing the 0.04 Ω figure, he's talking about copper-clad aluminum, rather than copper. But, if so, he should say so.