Sometimes managers want flight plans to be spaced on even WGS84 UTM XY coordinates for N-S or E-W trending rectangular grids.
For example you make a flight plan and lets say the line coordinates for the first line UTM endpoints are 445697.63, 5091362.17 & 445697.63, 5091662.17. In this one example, you want to shift all lines relative to this first line to be evenly spaced starting with 445700.00, 5091360.00 & 445700.00, 5091660.00. The ability to shift east or west or north or south, the WGS84 UTM coordinates after making the flight plan and prior to flying.