Adaptive CBC (ACBC) is a more expensive subscription. The software has been more complicated for us to develop and maintain the code compared to CBC. Plus, the design algorithm (which runs in real-time as the respondent is answering the questions) puts much more load on our hosting servers (Sawtooth Software offers free hosting for up to 50K completes per month) than CBC, which adds to Sawtooth Software's internal costs. ACBC has much more flexibility in terms of questionnaire design, making it a more advanced and powerful tool in many respects compared to CBC. And, I'd add, typically the tech support issues ACBC raises are more complex and require more of our tech support and software developers' time than CBC. Those are some of the reasons it is a more expensive subscription.