Is there a term for analogy that highlights contrast or differences?

Let’s consider the trite and corny analogy in this hypothetical TV commercial I just made up:

*-We see a little boy write his name and address on a little piece of card, he adds the words ‘please write back to me’, then he attaches a ribbon and ties the other end to a helium balloon and releases it into the sky, gazing, puppylike as it disappears from view.

-Camera pans out and we see his father standing right next to him. The kid looks up at his father and asks “when will someone find it and write back to me, daddy?”
The father replies “well, son, we just don’t know - we can’t tell where that ballon is going to go, we can’t tell when, where or even whether it will be found, and if found, whether the finder will bother to respond”

-The father now turns and addresses the camera, as it slowly dollies in to his face, “But you know, it doesn’t always have to be like that - technical support calls to [SomeCorp] will always be answered promptly, by dedicated, trained helpdesk consultants right here in [YourCountry] - at any time of night or day, we’re right here waiting to help you”*

(sorry about all that, it’s the best I could come up with at the moment)

Anyway, this is an analogy (the analogous part being: trying to communicate, hoping for a response) in which the differences (uncertainty vs reliability) are the key purpose. Is there a specific term to describe it?

Don’t apologize; that was actually better than about 90% of all TV ads I see normally. Maybe it’s time for a career change? :stuck_out_tongue:

Anyhow, I don’t know if a name for this type of analogy, but I think the general term for when you use (e.g.) the badness of A to demonstrate the goodness of B, A is acting as a *foil * for B. Maybe that’s not what your after, but it’s all I’ve got.

I thought it was “compare and contrast.” But I could be mistaken.