I won't tell you which one is right but I will offer an explanation as to why they are different.

Your case D31 combines several shocks that have their own combination rules. The Control Parameters list show these rules - Directional Combination Method (default is absolute) and Spatial Combination Method (default is SRSS). "Directional" controls the summation of shocks defined in the same direction and "Spatial" controls the summation of the different direction shocks.

Your Static/Dynamic Combinations have their own combination directive. This setting is found on the Combination window. The settings are absolute and SRSS. I believe the default is absolute.

I suggest you compare your numbers after rerunning the analysis with the same settings throughout.

= = = = =

A separate matter...

The force response spectrum approach that you are using ignores the timing of each "hit" in your system. Force response spectrum analysis is good for looking at a single impulse but I would point you to time history analysis if you wish to see these 30 events working one after the next, together in time.