RAM SS response spectrum S.F. & frame shear force difference.

Hi,

I have two questions.

1) RAM SS has response spectra input window and I need to input X and Y Scale factor(default =1.0).

Should I input I(importance f)/R there as starting point? or I/R is already reflected? In other words, 1.0 is ok to use?

There is no explanation for the S.F. on website or manual at all.

2) For frame shear force from response spectrum analysis, output shows "shear-Y" and "Change-Y".

I want to figure out frame shear force to design diaphragm. I believe I need to use "Change-Y" force value since it correctly combine

modal results. (Not the each floor "shear-Y" force difference). 

Thanks,