Can I use one license for a revised edition?

It depends on whether it's the same project or a new one:

• Revising the same book — fixing typos, updating the manuscript, refreshing the cover, even a "second edition" of the same project in your library — is covered. Re-export as much as you like at no extra cost.
• A different title — a new project, a separate book — is its own purchase.

Rule of thumb: if you're still working in the same book in your library, your license still applies. If you started a fresh project, that's a new book. See What does "per book" mean?