My guess is that you registered as a non-native English speaker when you set up your campaign? That would add 250 books to your publication goal, the reason being the additional cost of editing out the language quirks of someone not fully conversant with the language. But what I’ve seen of your correspondence and writing suggests that this is not going to be an issue. You could probably email Inkshares to change this.
The other way you could have gotten the extra 250 books on your goals is to have requested a $5000 advance. There, too, you could email Inkshares to change it.