It's important you tell us your experience. Sometimes there are bad batches and it happens with even the best of sources. It could be anything. Sometimes chemicals test as 99% but they aren't as effective because the raw materials aren't good or there were production issues. A good example is chiral molecules, which have two stereoisomers. Sometimes you get too much of one of the stereoisomers, and the drug will test well, but be ineffective. Shit happens. You never know. The best thing is to tell your experience because then we can compare experiences and let the source know if they have to go and look at a product more closely.