In this case first one is better. You need 2 measures, might sound like duplication but the logic is simple SUM ( Table[Column] )
For second scenario:
you will have to use CALCULATE ( SUM (), Type = “Cost” ) + CALCULATE ( SUM (), Type = “Charge” ) and every subsequent measure will depend on this, the moment you start iteration and nesting, understanding why the code works or doesn’t work will be a nightmare.
Both columns might have different data types so that can be a problem, you are going to increase the number of rows, not a problem with Power BI but I don’t know how huge your data is.
You won’t be able to establish any relationship between 2 columns, maybe you need to use Scatter plot, then you can’t put them on separate axis.