Question about annual Business/Education plan upgrade

Hello,

I currently have questions regarding the annual Business/Education plan billing.

Let’s say I purchase the annual plan for 50 users. If, after three months, I need to upgrade the plan to 100 users, how is the billing handled in this case?
Is the difference charged on a prorated basis for the remaining months?

Or is the plan renewed from the date of the upgrade with a new annual billing cycle?

I would like to understand how the upgrade process works for annual plans, so I can plan the subscription properly as our number of users grows.

I already subscribe to the 50-user business plan with a monthly payment. I've sent several emails to the NextDNS sales team but haven't received a response.

Thank you in advance for your clarification.

Best regards,

Jose Luis