LabelSeries with Stacked Vertical Bar Series

Hi, I have some issues with labelSeries when using it with a vertical Bar Series (so stackby="y"). The label seem to always go way above the bars like that:

I've done a codepen to show my problem. https://codesandbox.io/s/5kx21nk77l

Is there a way to get around the problem or maybe i'm doing this the wrong way (i used this tutorial ) ? I've tried negative values and reverse the labelSeries position in the XYplot but i don't have consistent result ...