Both methods will give you the same stress results. Only the forces and moments and displacements would be different, but we don't review those results for combination load cases. There is another difference in your cases however. In the first set you have SRSS'd your results prior to adding them to SUS. In the second set you did not do this, but considered the different seismic directions separately.
_________________________
Loren Brown
Director of Technical Support
CADWorx & Analysis Solutions
Intergraph Process, Power, & Marine
12777 Jones Road, Ste. 480, Houston, TX 77070 USA