Question:

How can I use macros to keep from repeating commands for every condition?

Answer:

When you want to calculate the same thing for several loading conditions,
you can use a macro to represent the calculations.  For example,

  MACRO CALC
    SUBTITLE
    \Condition: %1\
    PAGE
    SOLVE
    STATUS WEIGHT, DISPL, WPL
    RA /LIMIT
    LOAD (*) = 0
  / 
    
  LOAD (tank1, tank2) = .95
  LOAD (tank3) = .50
  .CALC "Departure"
  LOAD (tank1, tank2) = .10
  LOAD (tank3) = .50
  .CALC "Arrival"