That clarification about PyMuPDF losing the 1.5/2/4°C column mapping is important; once geometry is discarded, adding labels later would be reconstruction rather than enrichment. I would make that loss explicit in chunk metadata, for example table_structure=caption_only, and route those tables to a layout-aware parser or abstain from cell-level answers. A separate chunk-answerability check can then ask whether the chunk alone preserves every coordinate needed to interpret the value, while recall@k remains purely a retrieval metric.