He measures the current and the supply voltage. I suspect he does not put a voltmeter across the QX as he provided a high voltage pulse every 8 seconds or so. Hence "unwilling to measure directly like any normal person." is not true.
You just failed to understand it.
If he measures the supply voltage then we might be ok, but I haven't seen anything suggesting that he did measure that voltage. Can you point me out to where I can find that info?