I sent this question to Apple and received the following response.
Hello,
Thank you for contacting Apple Developer Support regarding the iOS Developer Program.
In regards to your request, it is important to note that the Enterprise Program is intended specifically for the development of internal applications for use by employees and contractors only. It is not intended to be a work-around for any device limits imposed by the 100 device limit of the iOS Developer Standard Program.
Before you will be able to purchase a membership in the iOS Developer Enterprise Program you will be presented with the terms and conditions of the Program License Agreement. We suggest that you begin an enrollment, and when presented with the Program License Agreement, compare the terms to your business needs and decide at that time if the program would be a good fit for your organization.
I hope that this information is helpful to you. Please let us know if you have any additional questions or need further assistance.
Best Regards,
Joe Carr
Apple Developer Support