Hi Jillian,
Thanks for reaching out! If you’ve purchased any licenses from us and would like to upgrade later to add more activation slots or daily imports, you can easily upgrade at any time right from your account. Just as you’ve outlined here, you’ll only pay the difference between your existing license and the tier you’d like to move up to. 🙂 You’ll find all the details you’ll need to get started on our Knowledgebase here:
https://theeventscalendar.com/knowledgebase/upgrading-a-license/
Simply place your desired upgrade in a shopping cart, then add a new license for Eventbrite Tickets from that product’s page, and you’ll be all set to complete checkout. Let us know if you should have any other questions as you’re working through the steps!