For SeriesDataLabel s and Trendline labels, the origin for the Y coordinate is relative to the default location of the Data label would in if DataLabelPlacement were set to 'Default'data label. If you set Y to a value is set that would put the Chart region off the chart, then when the workbook writes, the value will be clamped such that the region will still appear on the chart. The axis is such that larger Y values put the chart region lower in the chart.is outside the range of 0 through 4000 inclusive, the value will be adjusted to be within that range. |