I think one of the problems in this thread is the confusion of using
"phase" to refer to both true phases as in 3-phase versus the 180-deg
phase difference between the two hot legs of a single-phase AC circuit.

I don't know when it became prevelant or popular (if it actually is or
whether it's still fairly isolated) to refer to the two hots as two
"phases" but I spent a significant amount of time trying to break my
hired hand of the misconception over the last year. He was trained as
an aircraft mechanic and was/is pretty darn good w/ hydraulics,
mechanics, most simple wiring, controls, etc., but apparently was taught
this as gospel regarding single phase AC power...