Hi,
Tomas explained once that the new vibration level is calculated from all 3 axes - the old one was just using single axis. in addition the algorithm is more exact. seems now to be more like the results in the Spirit settings tool.
i've been seeing peaks 100+ with 3.1 too (and not with 3.0 before).... checked it with settings tool and y-axis showed the same. was easy to feel with fingers on the boom - in my case it was dead tail shaft bearings. now vibration level is < 50 even in hard 3d moves. ok, not a nitro, but e-heli