safe cell cross-check of results/U_007_1_cert.jsonl.gz: 200 of 728137 zone-A cells at prec=96 on 8 workers
    [20/200] min safe margin so far +4.08e-06
    [40/200] min safe margin so far +4.08e-06
    [60/200] min safe margin so far +4.08e-06
    [80/200] min safe margin so far +4.08e-06
    [100/200] min safe margin so far +4.08e-06
    [120/200] min safe margin so far +4.08e-06
    [140/200] min safe margin so far +4.08e-06
    [160/200] min safe margin so far +4.08e-06
    [180/200] min safe margin so far +4.08e-06
    [200/200] min safe margin so far +4.08e-06
done: 200 cells, 0 safe failures, 0 cells with fast>safe; min safe-method margin = +4.08e-06  (coverage of [0.07,1.0] established by check_cert_U)
