Nice work, NEOCortex.
I made a program a few months ago which does nearly the same.
The only thing missing is the calculation of the relative data of the target. But you don't need a huge spreadsheet program to use it, and you don't have to copy the formulas for every contact. Plus you can track as many targets as you want and you can enter imperial or metric ranges
TDC (couldn't resist naming it Target Data Calculator
)