Good evening Brian and welcome back!
Thank you for reaching out to us.
I would love to help you with this topic.
You currently own a business license which lets you install the Events Calendar Pro on up to 3 websites.
Furthermore you can always move your license around should you need to: https://theeventscalendar.com/knowledgebase/moving-your-license-keys/
The only caveat is that if you use a business license on a multisite WordPress install, you will lose the ability to upgrade the plugin automatically (from wp-admin) on that specific site.
Let me know if that helps.
Have a great day!
Geoff B.