Here are some diagrams which might be helpful --– snapshots of a circuit simulation.
Both circuits have identical total power consumed, just different 120V loads.
Trying to wrap my head around Harper's method of finding power usage: multiply average leg current by 240V --– 240 * (L1+L2)/2
. Mathematically, it's equivalent to 120V * sum of legs:
120 * (L1 + L2)
, so hmm.