Use different method and syntax that may help:
Code:
Dim MySeriesColl As Excel.SeriesCollection = MyChart.SeriesCollection
Dim TempSeries As Excel.Series = MySeriesColl.NewSeries
TempSeries.Name = "Temperature"
TempSeries.Values = "=(Globals.Sheet1!R4C16,Globals.Sheet1!R4C5:R4C16,Globals.Sheet1!R4C5)"
TempSeries.AxisGroup = Excel.XlAxisGroup.xlPrimary
R4C16 is "P4", R4C5:R4C16 is "E4:P4", R4C5 is "E4"