<p>Decision-making in complex, contested settings increasingly relies on decision-support software that shapes how groups compare trade-offs and stabilise collective judgements. This study examines a specific software, Multi-Values Appraisal Methodology, integrating the Strategic Choice Approach and the Analytic Hierarchy Process, through eight workshops in four European countries on urban transformation cases. Inductive analysis of participants’ reports and surveys distinguishes software affordances from outcomes. Findings show that shared visualisation, traceability and staged transitions support consensus building and dissent management, contributing to a “Plural Subject”, while the workflow alternates collective modelling with individual scoring to enable iterative and more transparent decisions. The paper clarifies how socio-technical affordances are perceived and actualised in workshop practice.</p>