If you select the same dataset for both the start and end points, the Duplicates combo-box will be enabled. This controls MileCharter's behavior regarding duplicate routes. The following chart was produced by MileCharter, and lists the distances between cities in Texas:
The above chart was produced by setting the Duplicates combo-box to Calculate all duplicate routes. Every pair of cities is represented twice, with a route distance for each starting city in the pair. There is usually a small discrepancy in the distances due to one-way road systems and freeway frontage roads.
Atlas and road map mileage charts usually discard the duplicates and plot the distances in a triangular chart. To produce a triangular chart like this, set the Duplicates combo-box to Calculate lower left only. The Texas city chart now looks like this:
If you prefer the opposite triangle, set Duplicates to Calculate upper right only: