jim rozen writes:

(4) Which is to say, regulators are inherently inefficient. They
dissipate some of the available work into (ultimately) waste heat or
work performed on the atmosphere.

Like gary says, "it's not in the regulator."

If you mean, the manifestation of the loss is not in the regulator
(instead in waste heat downstream, or work spent outside the system), fine.
The regulator nevertheless introduces and accounts for the loss. It sounds
rather coy and Clintonesque to say it is not "in" the regulator. That's
like whining that mechanical inefficiencies aren't "in" an engine, but
flushed out the exhaust. When you're wrong on the physics, you can always
retreat on the definitions.