It's a feature of our Unlimited Site Plan. Our Unlimited Site Plan is our best plan and that is an additional feature of our best plan.
If you would like to downgrade, you can do so. At the end of your Unlimited Site Plan's 30 day subscription period you can downgrade back to the 1-Site Plan. There are no pro-rated refunds on downgrades in these circumstances. Otherwise you would be receiving all of the benefits of the Unlimited Site Plan without paying for them and that would not be fair to those who do pay for the Unlimited Site Plan monthly.
If you have any other questions, please don't hesitate to ask.