HMC, the pressure in hurricanes varies. For instance, in 1992, Andrew was a tropical storm with an amazingly high pressure of 1015mb. Local atmospheric pressures can affect tropical system pressures, and they can have higher than normal pressures but still have much higher wind speeds, and vice versa. In 1999, Floyd reached its max at 150mph with a minimum pressure of 921mb. Last year, when Isabell reached Cat 5 strength, it's mininum was 920, and at one point it was a Cat 5 with a pressure as high as 938mb. There are many factors involved, but you don't necessarily need another 22mb drop to see a Cat 5 with Frances.