you can do something like :
Create a variable with expression .
and you can use that $(vSales) into multiple places it will work.
if you want to use Measure A and Measure B in the Same Chart you can try to Use:
Column(1) in Measure B so it will read the data Values of the column(1).
even I tried Expression Measure A label in Measure B it's showing an error in syntax but showing the correct value.