Floor Modal Base Action and Modal Base Action

Hi,

I am figuring out the way around to add ACCIDENTAL TORSION in STAAD analysis using EN 1998. I am trying to extract seismic force for each level. I read in one of the forums to use SET PRINT 17  command to show the shear forces for each modes. Result came with FLOOR MODAL BASE ACTION and MODAL BASE ACTION. My questions:

1) Please confirm if this approach is correct:

from Floor Modal Base Action Result, shear per level is determined taking the square root of the sums. Example from the snapshot below FZ = sqrt [(11471.79)^2 + (6968.33)^2] = 13422.35

2) What is the relation of Floor Modal Base Action and Modal Base Action? Does the summation of all Floor Modal Action should equate to Modal Base Action?

Thank you in advance.

Regards,

Julie