Dave Looman
Ansys Employee

Ansys can't provide information like.  For one, we don't have it, but also, we don't know what code would apply to your analysis.  I don't recognize 0.1 PF as a criterion for significance.  It would produce an effective mass of 0.01, but for a very small structure a mass of 0.01 could be very large.  So it's the ratio of effective mass to total mass that should be considered.  Missing mass is just for response spectrum (not just shock), but residual vectors (RESVEC command) can be used in a random vibration analysis.