Torsional irregularity ratio and modal analysis

In RAM Frame, when torsional irregularity is calculated using modal analysis (response spectrum), what does that value represent? Is it computed before or after combining modal responses? (I believe that the ratio should be computed for each mode first, then the highest ratio picked out.)

The way to compute it in ETABS is

https://wiki.csiamerica.com/pages/viewpage.action?pageId=4554971

so that we can know that a certain torsional behavior is associated with a specific mode. Is there an equivalent approach in RAM Frame?

Please note that I understand how it’s done with ELF loading

http://communities.bentley.com/products/structural/structural_analysis___design/w/structural_analysis_and_design__wiki/2980.ram-frame-seismic-loads-faq

and that my question is in fact different than what is addressed there.