There can be two reasons why your EUR invoice may change month after month.
Orders are being moved to a new renewal date
By default, our system creates an order for one month (if you choose a monthly billing cycle). After the first cycle, it will be automatically synced with your account's renewal date.
This means that on the first invoice, you will see the full amount. On the second invoice, you may see a smaller amount because the second invoice is prorated so that it can be pushed to your account's renewal date. You will see the correct amount on the third invoice because your order has been synced with your account's renewal date.
Our system's base currency is USD (United States Dollar). If you use EUR as your account's main currency, we will use that day's conversion rate to convert your costs from USD to EUR. The conversion rate used for your invoice is included in the notes section of your invoice. The currency exchange rate is updated once a day at midnight.
If you still have questions, please contact our billing team.