Mechanically, results from Janoshik are only comparable to other Janoshik results, not to results from any other laboratory, because the methods differ.
A result significantly outside the database range for that vendor and compound is either a real difference in quality or a different material than the database entries.
The cost of testing is by sample submitted, not by parameter measured, so a single Janoshik result gives you purity, content and identity for less than most suppliers charge for purity alone.
Janoshik publishes summary statistics on their website, including the number of samples tested and the range of reported values, giving you a baseline for comparison.
I would use Janoshik for the first lot from a new supplier and occasionally for spot-checking, not for every lot.
Keep Janoshik results to compare across suppliers and across time.