This paper demonstrates that interprofessional meeting talk in the activity type of weekly meetings for optimising maintenance plans on offshore oil and gas wells on the Norwegian Continental Shelf, is marked by shifts between discourse and activity roles in intricate and overlapping ways, thus providing the meeting participants the chance to cumulatively add to the joint decision making based on their organisational role-responsibility and skills. This study indicates the need for further distinction of role categories in the participation framework, in particular concerning professional/institutional discourse.