Abstract: Cost systems are fundamental to accounting, as they produce key information to evaluate the economic performance of the firm. Drawing on ANT conceptual theorisation, this paper aims at investigating how a cost system is produced, promoted and maintained by a network of actors, over time. Informed by an in-depth qualitative field study in a French public social housing organization, we analyze the cost system as a dominant, consensual and accepted calculative frame, resulting from a framing process. In particular, we examine an episode of contestation of the cost systems features. Highlighting the different perspectives on how costs should be calculated, notably amongst the accountants, the analysis emphasises the role a dominant coalition play in the promotion and maintenance of the cost system. The analysis also shows that certain framing could persist across time and networks.