VBA - Coloring Individual Parts Of Data Label?

I have plotted a chart through VBA and I am appending some information to certain data labels. This appended part is being turned a different color depending on if a corresponding value is less than or greater than 0.

Code:
For i = 1 To cht.SeriesCollection(1).DataLabels.Count
If ws.Range("C" & i + 1).Value < 0 Then[code]....

In stepping through the code, I notice that it works until the color switches twice. So for instance, if the first 3 points are below 0, it turns the appended part of the data label red. Then the next point is above 0 and it turns it green. Then the next point is below 0, and at this point it turns the appended part of EVERY data label red (overwriting the previous green one). It keeps going like this until all of the data labels are either red or green, depending on whatever the last value is as it just keeps overwriting.