What is the range of effect for the Infinite Probability Drive?

Inspired by this exchange in chat:

Jack B Nimble @ScienceFiction&Fantasy Brought you to by someone who doesn't understand probability.

phantom42 @ScienceFiction&Fantasy Zaphod just used the Infinite Improbability Drive at exactly the wrong time.

BESW @phantom42 This is my new third-favourite explanation for improbable things in fiction.

The Infinite Improbability Drive "passes through every conceivable point in every conceivable universe almost simultaneously".

In the books/movie, we see not only the Heart of Gold and its passengers affected, but we also see things outside the ship affected (e.g. missiles being turned into a sperm whale and a bowl of petunias).

Is there any indication of the maximum distance from the drive that reality or an object can be affected?

*Note: I am not asking about the maximum travel range of the ship/drive, but about how far an object can be from the ship/drive and be affected.