Liquids are sold by volume not weight. Powders are sold by weight not volume. Our powdered products fill the bottle close to the top when poured, but over time settle. Some formulas settle more than other formulas. I am certain all of the chemical manufacturers in the industry take steps to prevent this from happening. I would return any product that you have any concerns with to the distributor who will look into the matter for you. We package well over a million units every year. The Utah division of weights and measures audited us recently. It took them a few hours to look at a couple of products, which had no issues. They have made it a new initiative of their division to start making regular visits to manufacturers to do unannounced testing, which is something we support wholeheartedly. As mentioned before we take several steps to prevent any of these issues including a planned 1% overfill on liquids. If we error, we are confident it is to our detriment, not benefit.