Shutting down your PC: Frugal fact, or financial fiction?

In "Guy vs. Guy: Shutting down your PC at night: Money saved or productivity lost?", tech guys Rick and Dave square off, pitting thousands of dollars in potential business savings versus the productivity lost in turning your machine on and off each day.

Rick's take: For 10,000 computers, you can save $260,000 per year by using the power button on a daily basis. That’s $26 per computer, per year.

Dave's take: "I lose more than that due to gas evaporating out of my gas tank." Dave says under the assumption that an employee is a a typical knowledge worker making $80,000 per year, or roughly $40 per hour, that means all that time lost (10 mins startup in the morning, 5 mins shutdown at night) costs the company about $2,500 per employee, per year.

Their full arguments are here.

So whose math is correct? (Or neither?) Tell me why in TalkBack.