With rounding, Nexa was 67 mg, 71 mg, and 72 mg. Put that way, Nexa doesn't seem as bad as I thought (but still makes me wonder about the next vial to be tested after the R12 issue).
For comparison, Uther's test results are 68 mg, 68 mg, and 70 mg for T60 (for $180 and less at UtherPep).