What does Mitt Romney's “Telephone Tips: ‘Just Left,’ 25 cents; ‘On His Way,’ 50 cents; ‘Not here,’ $1; ‘Who?’ $5.” mean?

There was the following paragraph in Maureen Dowd’s article titled, "Mitt Romney is the president of white male America” in November 10 New York Times:

Maybe the group can retreat to a man cave in a Whiter House, with mahogany paneling, brown leather Chesterfields, a moose head over the fireplace, an elevator for the presidential limo, and one of those men’s club signs on the phone that reads: “Telephone Tips: ‘Just Left,’ 25 cents; ‘On His Way,’ 50 cents; ‘Not here,’ $1; ‘Who?’ $5.”

As it is customary to her writings, I was puzzled with the sign on Mitt Romney’s phone: Telephone Tips: ‘Just Left,’ 25 cents; ‘On His Way,’ 50 cents; ‘Not here,’ $1; ‘Who?’ $5.

Can you decipher for me what this line means?

Here's an example I found by googling:

That is the kind of sign one might see in a sports bar or some other drinking establishment where men go to drink without the supervision of their wives, girlfriends, etc. It's intended to be for the bartender, indicating the gratuities he expects for each answer.

Say you're a patron of the bar. Your wife calls, and you don't want to talk to her. Bob, your favorite bartender, asks "Who?" You would be expected to tip Bob $5. Look at it as a list. For the bartender to answer "He just left" would only cost you a quarter, but that isn't as good an answer from the standpoint of someone who might not want anyone to know he had even been at the bar.

Note that this is not a real practice. It's just meant to be humorous. The macho indifference of the patrons to people calling for them while they're drinking is supposed to be funny, expressing how important it is to them to be allowed to get drunk in peace.

This is similar to the signs you see in repair shops:

RATES: $25 an hour. $50 an hour if you watch. $100 an hour if you help.

Not meant to be taken seriously.