Everything in speaker design involves trade-offs. This is most evident when looking at bass extension, sensitivity, and cabinet size / volume. Unfortunately there are speaker manufacturers provide bass specifications that are suspect at best. There's obviously posturing involved in order to increase sales and tell potential buyers what they want to hear.
From time to time I have customers asking if it's possible to have deep bass extension and high sensitivity in a moderate size (or even small) sized cabinet. In some situations they quote numbers given from other speaker companies and the woofers are drivers that I've used in previous designs. This often presents a problem if the information given me doesn't line up with my own personal tests. After having designed 100's of speakers I can pretty much look at specifications and tell you if they are reasonable.
Part of the problem is there are different ways to take and interpret bass measurements. The best two ways are anechoic or nearfield tests with nearfield primarily being what I use. You can do in-room curves; however, resolution (accuracy) is often skewed by acoustic problems in the room. Some companies don't even measure at all and rely on software simulations or an "optimistic" guess from their sales and marketing people.
My solution is a simple one - just tell the truth and strive to be as accurate as possible.
Rick Craig, Owner and Designer