Meter-feet issue in xy scatter plot

Hello!
I am trying to make one XY scatter plot wherein y axis is to be shown in both meter and feet for the same x axis values. I have plotted using primary y axis in meter and secondary y axis in feet. Ideally x values should plot at the same place i.e. superimposed one upon another. I have attached the plot. Towards top and bottom x values are found plotted at different places. However, at the middle of the chart x axis values corresponding to both y axis are at the same place i.e. superimposed.
Why it is happening like that? How the x axis values can be brought at same places?
Request guidance. Thanks.

Hi,
The value of the depth in meters are not exact : m = feet/1000*12*25.4
The Y axis for the depth in feet and meter should be related : increase 50 feet for main unit Y Depth(ft) = 50/1000*12*25.4 = 15.24 increase for main unit Y Depth(m)
Note : it's not possible to enter a formula on the main unit
Best regards

Hi jpr73
I could not open the attached file. Please check it. I did not understand reason for multifying with 25.4. Did you mean 30.4? Thanks.