Assessment in higher education is often a balancing act between fairness and the inherent complexity of standards, with evaluative judgement playing a crucial role in determining the quality of student work. This study employs a sociomaterial perspective to investigate the often-obscured justifications used by examiners during real-time moderation meetings, as well as their role in shaping judgements. Through participant observation and focus group interviews, a two-stage analysis was conducted. Thematic analysis identified four categories of justifications -- predefined, personal, norm-based and other justifications -- highlighting a range of rationales behind examiners' grading decisions. Subsequent interaction analysis explored how these justifications inform the evaluative judgement process, revealing their role in co-constructing an understanding of fairness to reach a compromise. A key finding is that different perspectives on fairness significantly impact evaluative judgements. The study recommends the use of the concepts 'tinkering' and 'rupturing' as analytical tools to promote flexibility and harness the strengths of subjectivity while maintaining the integrity of judgements.