I can't find the source but I read somewhere that when Facebook makes you an offer they make it one level lower than where you are currently at as a matter of policy.
Also, some smaller tech companies will inflate titles to try to compete for talent. Like I met someone who's a VP of engineering, they have a total team size of 2. That's not the same as a VP at Facebook. If that guy got an offer for one level lower, that would be a huge step up.