I think I understand what you're getting at but I imagine this is beyond the scope of AnabolicLab.
Are you suggesting to send the sample elsewhere to acquire the concentration?
That depends on if you trust the "elsewhere" laboratory.
I had a trustless approach on my mind - where you have no need to trust a 3rd party.
Purchasing a raw material, accurately weighting it and using a graduated cylinder to dissolve it is a sure way to assess for that kind of systematic error.
You weight 10 or more grams of nandrolone decanoate - a scale costing 20 dollars can weight that with very high accuracy. You can verify the accuracy by weighting coins. Error can be kept at around 1%.
You put it into a graduated cylinder (or better yet, volumetric flask) and dissolve it. You can verify the accuracy of the cylinder by weighting distilled water.
Now you have a solution which contains maximum of x mg/ml nandrolone decanoate. I say maximum, because if you don't have the raws tested, you can't be sure, but I don't think I've ever encountered seriously bad deca raws.
If the result from any lab is significantly higher than x mg, you got the answer.
If it's lower, then either the lab is bad or the raws were bad.