The tool is designed to help editors and the W3C Director ensuring that their references are properly identified as normative when needed. It is using some random heuristic to find normative and informative sections, as well as the references section(s) itself. If the reference appears in an informative section, it simply ignores it. For the other references, it classifies them in 2 categories: normative references and others (appearing in reserved order on the report). Based on the context, it may be that you're missing a normative reference, or that you're not using the normative references guidelines.