It's my understanding fewer are anechoic than in-room measurements. And, when revisions are made in subsequent versions of a speaker, one needs to ask if they truly went back and retested both anechoic and in-room measurements again.
Sensitivity listed on a line item ad seems to be more of a general guideline at a selected frequency range noted on basic tech spec sheets. Seems to vary from one manufacturer to the next on what frequency they are sharing with you. Gotta look at the actual graphs across the entire frequency range to get a better handle on what's actually taking place with a speaker; where the dips and peaks are.