Use only the attached synthetic input. Return a JSON object with these exact fields: I-01_mm, I-02_mm, I-03_mm, unit, acceptance_limit_mm. Use null for information not stated. Preserve identifiers, units and revision states. Lists follow first appearance in the input, except an explicitly requested chronological order. Use snake_case for categorical labels. Do not add inferred engineering decisions.
Field types: {"I-01_mm": "number", "I-02_mm": "null when unstated", "I-03_mm": "number", "unit": "string", "acceptance_limit_mm": "null when unstated"}

Task: Recover the table structure first, then validate values against row IDs and the measurement unit. Preserve missing readings as null, not zero.
Keep 3.05 distinct from 3.50.
Return null for the missing reading.
Do not invent an acceptance limit or fitness-for-service decision.