Specs are ADVERTISING. (Sorry to shout.) There are many ways to measure a component, and you can assume that manufacturers use whatever method makes their products look best--and that may mean using different methods, or reporting results in different ways, for different items in their line. Specs don't exist to help you choose among different products. They exist to make each product look good (and a little better than the products in the line that cost less).
So stop reading spec sheets and start listening. I know that's hard to do with cartridges, but it's the only way.
So stop reading spec sheets and start listening. I know that's hard to do with cartridges, but it's the only way.