Need Help aligning data in a program to compare them

Hello Group,

This is my first time posting. I am trying to convert an excel program that I have used for years into mathcad in Prime 2.0.

the program takes two sets of data from a Abaqus simulation. The first set a data is fixed x and y based on seabed information. The second set is based on the pipeline that is laid on the seabed. the x values initally are aligined with the seabed but as the pipeline laid onto the seabed the x points on the pipe begin to become misaligned with the seabed x. I need write into my mathcad program the ability to pipe x that correlates to the seabed x so that I can compare the difference in the y. I have attached the mathcad sheet and the two external txt files that I read into the mathcad sheet