Torsional Moment as per NBCC2005

[canstruct]

Torsional moment according to Clause 4.1.8.11(10) say ex+0.1Dnx. But according to commentary page J-49 explanation according to clause 4.18.11.(9) 178. says 0.05Dnx also for flaxible diaphragms, as in the case we have flexible diaphragms, can we use 0.05Dnx for torsional eccentricity. If anyone knows more about steel structural seismic design, kindly explain this clause. I understand that for rigid diaphragm Code says 0.05Dnx unless shear walls are exactly at centre of mass. Kindly be specific to Latest Canadian Code only. Appreciated for clarfication in this regards, as there is a confusion amongst engineers for use of accidental torion.