Can “It’s” Mean Both “It Is” and “It Has”?

Ordinarily, I wouldn’t think twice of writing “it’s been” instead of “it has been.” Contractions are critical, and my meaning is clear.

But my wife pointed out that “it’s been,” technically, means “it is been,” which is obviously wrong.

Who’s right?

My colleague Paul says this:

A few English contractions can have two or more meanings. Lyrics with past-tense contractions like “It’s been a long time” and “It’s been on my mind” are found routinely in popular songs and showtunes. Likewise with “She’s been on my mind.”

In other words: I’m right. ;)