Non-production sites are limited to half of your total sites (rounded up). However, to provide maximum flexibility, this limit is not strictly enforced.
If your non-production sites exceed this limit, then once per day our system will apply an adjustment charge. This charge is equal to the number of excess non-production sites multiplied by the difference in daily cost between a non-production site and a production site. It will appear as a charge for "Excess Non-Production Sites" in your account activity and history.
If you have multiple accounts with non-production sites, the charge will be allocated proportionally, with remainders allocated randomly.
If you have many sites eligible for the non-production plan, this charge can eliminate the need to choose some to make production unnecessarily and ensure you are automatically charged the minimum possible for the number of sites you have.
If you prefer to avoid this charge, you can promote your excess sites to a Production plan, consolidate multiple non-production sites with features like per-alias document root, or remove excess Non-Production sites.