What I call "true labels" are the labels bound to the series on a chart. If you chose Chart Options on your pie chart and go to Data Labels and check the Value option, it will put a label on each slice of the pie chart with the value of that slice. Each time you change the value of the slice, the Data Label will change also. If you move the slice, the Data Label goes with the slice. If it doesn't, it looks like you have the "labels" of each slice as a text box on top of the chart. That way, when you move the slice of the pie chart you have to manually move each "label" (in this case they are text boxes, not labels).
Hope it is clear for you. If you need further assistance, It would be better if you could post some sample sheet for us to have a look at it.
jppinto