Wind load distribution on semi-rigid diaphragm in a user-defined story forces

I am trying to model a 4 story building with the first story having no wind exposure. Using the concept described in the following RAM wiki,, I tried to define the user defined story forces by using the output from the building model with wind exposure to only the top three storys. 

Applying the loads in user defined wind story forces seemed simple enough for Rigid diaphragms. The Roof in the model is defined as semi-rigid diaphragm. For semi-rigid diaphragms, when I applied the force, the distribution of applied story forces did not match with that of the auto generated wind forces from the wind load case. See below.

Fig-1:  Auto generated wind-load distribution on semi-rigid diaphragm. 

Fig-2: User-defined wind load distribution on the semi-rigid diaphragm. 

I applied the same force as displayed in the "loads and applied forces" report output. If the eccentricities come into play for the wind load distribution, then it is definitely not given in the output of the report. Is there a procedure I can define the appropriate user-defined wind forces for semi-rigid diaphragm? Or a better way of modeling a 4 story structure with no exposure to the first story? 

Could anyone please help me out with this? 

Thanks in advance! 

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