Stated carefully, start from what the certificate claims to measure and what the claimed measurement actually answers, because those are two different questions.
Multiple testing on the same lot reported in a single document suggests internal quality control; identical figures across different lots suggests the same certificate reused.
Concretely, the test date matters because a certificate six months older than the vial is not evidence about your material, it is evidence about what the material was like half a year ago.
The standards that exist in this space — ICH Q3A, Q3B and various pharmacopoeial chapters — are worth reading once even if nothing you test is obliged to meet them.
One qualification: a single result from a single vial at a single time is a point estimate with no error bar, and no amount of decimal places changes that.
My working rule is that a document without a lot number, a method section and a test date is marketing.
edited 23 Jul 2026 by Dr_Nadia_Farsi — expanded the table to cover the lower concentration