Hi! Overture is its own separate side-zine with completely different content from Unfinished Symphony, so it's an add-on you can only purchase under the Bundle 1 listing. Since Bundles 2, 3, and 5 already come with a complementary PDF of Unfinished Symphony, you only need to purchase Overture on its own from Bundle 1. But if you're only interested in the digital versions of both zines, you may purchase both at a discount of $25! The ability to automatically discount both PDFs in our stores is why it's not listed along with the add-ons. Hope this answers your question! ^^