I updated your post above to add the histograms for the two images.
In this case I would not worry about the histogram being pushed to the left. These are indoor shots using flash so the backgrounds are going to be dark. Your subjects are properly exposed and nothing important is lost in the shadows.
In fact lookin at the on the right side, if you had exposed brighter you may have lost some highlights. The dynamic rage of the light is greater than the camera can record. In this case it is better to sacrifice the shadows.
The right side of the histogram is usually more important than the left side. If you overexpose, histogram bumped up against the right side, there is little room for recovering those lost highlights. The shadow detail is more easily recovered, especially at low ISO.
When you have a scene like this, that has a dark background, you can use active D-Lighting to help bring up the brightness without overexposing the highlights.