Floorvibe version 3.1 utilizes analysis procedures in the 2nd Edition of AISC Design Guide 11, while version 3.0 is based on the 1st Edition. Calculations based on the 1st edition tend to underpredict vibration for walker paces less than 100 steps per minute.
We are working with the good people at FloorVibe to implement this update. It may require a separate installation of FloorVibe 3.1.