This article reports on a systematic, controlled case study where a preservation plan is created for a large collection of audio material using the planning tool Plato 3, and takes this study as a starting point to assess the state of art in scaling up decision making processes in preservation planning. We report on the effort required for specific preservation planning activities such as the evaluation of potential preservation actions and the specification of evaluation criteria. We compare this with a number of improvements to the planning process and tool that are developed as part of the SCAPE project, analyze the status of improvements and the limits of automation, and outline future steps towards scalable preservation decisions.