Mark,
What an interesting thing you've dug up.
I fix welders at work and when you consider that MIG welders are pretty easy on the supply, when used with an Argo-shield gas and non-fluxed wire, they don't tend to upset the supply all that much.
However, when you start using a MIG with flux-cored wire (as in no shielding gas) the welder has to work that much harder, as the welder has no gas to cool the liner towards the torch, this causes friction.
Your current will increase, accordingly.
Liner failures are common with gas-less MIG welding.
And that is only with steel, other metals like stainless or aluminium are an acquired taste.
But then again, if you can TIG weld aluminium is easy to weld.