A field set to ? is unknown: the min–max range is computed by trying the most severe and the least severe value. On optional metrics (temporal/environmental), X is the specification's “Not Defined” and is scored with its default value. The score is assumed to be monotonic with respect to each metric's severity. ⚠ warnings flag value combinations that look inconsistent between the two versions; the rules are heuristic, not part of either specification.