Organizations, leaders and teams vary in their definitions of consensus, usually on the question of the percentage of any group required for a decision for the whole and time considerations. Because many groups don't have a good model for collaborative decision making, their exprience is that unless it's a straight vote, the time required for building consensus is in direct proportion to the numbers of complexities of people engaged.
When people collaborate on decisions to serve the whole, there is less emphasis on quantities of participants and more on quality of process. The assumption that because I'm involved in a process it's a better process is an honest albeit questionable assumption. More people don't make a better process. A better process makes a better process.