Dynamic response combination. Steel Design

Hi everyone, 

I am carrying out the dynamic analysis of a simple structure. The combination method of the response spectrum is defined as CQC (see first picture attached). However, the report file shows the different base shear values for different combinations methods (SRSS, CQC, ABS...) My question is, which one is the one selected to carry out the Steel Design of elements?

Furthermore, despite the different base shear results coming from the different combination methods included in the report file (second picture), none of them matches the result of suming up the reactions in the base of the structure for the Seismic Load Case analyzed.

Thank you very much in advance