You should be creating independent NumericLabel objects. They will have no tie-in to the bars in the graph. It is up to you to position the NumericLabel objects above the floating barrs.
You can use the NumericLabel constructor that specifies an intial value, or your can set the value of the label using the NumericLabel.NumericValue property.
If you don't specify a value, a numeric label will default to 0.0.
You must create a new NumericLabel object for each bar you want to label.
double x = 20;
double y = 10;
double labelvalue = 0.25;
// set the value in the constructor
NumericLabel barlabel = new NumericLabel(pTransform1, labelfont,
labelvalue , x, y, ChartObj.PHYS_POS, ChartObj.PERCENTFORMAT,1);
chartVu.AddChartObject(barlabel );
// or set the value using the NumericValue property
labelvalue = 0.35;
barlabel.NumericValue = labelvalue ;