Scatter plot - series plotted incorrectly (?)

I'm having trouble understanding what the chart is supposed to be showing. Here's what I see:

1) A basic scatter chart with two data series. Series one is "average maturity" and is using column C for the X values with column D for the Y values. Series two is "total savings..." and is using column C for the X values and column G for the y values.
2) Series 1 is formatted to be invisible (white on white) and to be plotted on the primary vertical axis. Other than being invisible, it appears to be plotting correctly (the y values in column D match the vertical position on the primary axis).
3) Series 2 is formatted to be visible (orange) and is plotted on the invisible secondary vertical axis. Making the axis visible so I can compare the values against the axis, and series two also appears to be plotting correctly against the secondary axis.

Based on the current chart design, the chart appears to be doing exactly what it is being told to do. I don't understand why one would format series one to be invisible or format the secondary axis to be invisible in this case. If I format the invisible elements to be visible, the chart looks correct. I guess the real questions are -- why are these elements invisible? What are you really trying to do with this chart?

Are you trying to display a data label with a value that is not the x or y value?

If so rather the 2 series and a secondary axis look at the 'Value from Cells' option on data labels of the first series.