Galaxy encourages users to retry and refine their strategies given the same resources.
Currently, "Previous Clear Resources Used" is not shown if you are missing ships/stats (ie cannot repeat previous clear), such as if you select a different ship to build from the L1 node at the start of the galaxy. This means that you can only tell that this new strategy might be better for this later node if you use the same ships/stats, or separately keep track of how much you spent on it before.
It is shown in the battle screen if you clear the battle, but it may be useful to have it available from Galaxy view--such as to view the potential change over multiple nodes, such as in Galaxy 2 where you might compare B3A+B4A+B5 to B3B+B4B+B5.