Dynamic Format DAX measure calculating variance

This is my first time creating a DAX with Dynamic format - The idea is I have a Clustered Column and line chart. the clustered column will have Last year values (when I say last year values its dynamic based on filter selection say its OOS, SE or NWAU) and current year values. Now I want the line chart to have this dynamic formatted DAX to show the variance between two years- essentially the difference and the % of difference. I am doing the first step of achieving the right difference and then add the % as a detail or incorpoorate in the same DAX.

I am having 3 values blown out of proportion. The percentChange column is the expected value and the VarianceFY_Metric 10pc is what I get from above DAX

Kindly help fix this issue