Use of Offset command

Sir,

Here I attached a STAAD model and a photo of 3D view. In this model I have column5658.Structure1.stds of size 18"x9" with different orientations. Columns are not flushing/aligning with walls (some locations as marked in attached photo), due to STAAD makes model with center line .Similarly beams are attached with columns only in half depth. So what should I do to make this type structure like real structure?

1. If I analyse this structure without changing (i.e. without using offset command), how results will differ from actual results?

2. Should I use offset command for columns at start and end points to get accurate results? 

3. If I use offset command for columns then here will be any eccentricity of columns at footing or not (as column is shifted from lowest node due to offset)? (Footing center will be at node, while column center will not be on node). If column will be eccentric then BM will occur in footing. 

4. Should I use offset command in (-) Y direction for beams to align column and beam tops?

5. If I use offset command and after analysis I design with RCDC then how column  position will be shown in RCDC (actual or shifted)?