I don't think oil analysis is all that super accurate, the methodologies used may not be bulletproof and variables such as equipment, operators, etc. certainly affect it. I bet if you sent the same sample of oil to the same lab on 2 different dates you'd get different results. Notice how the results are whole numbers, and not taken past the decimal point (ie your Aluminum is reported as 1 not 1. 2 or whatever). That's because when there isn't that much of a certain contaminant or product in the oil it's gotta be pretty tough to analyze the exactly how much there is in there. Ansd the number isn't hard fact, probably more like a good estimate.
I service medical equipment by trade, and during testing evaluate performance and record results. Often readings jump around and it's impossible to record an exact number. You write down the median of the range or the average, using your best judgement and experience. I'm guessing oil analysis testing is similar to this and subject to interpretation and the experience of the tribologist or whatever they're called (oil techie).
Vaughn
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