Other option could be using graph builder and getting formula from smoother:
1. Change Curve modeling type to nominal
2. Create smoother graph with Curve as overlay and change settings to fit the lines
3. Click on the red triangle on Smoother and select Save Formula
4. Now you should have a formula in your data table
5. With the formula you could then add "missing" voltage values for Curve 1 (add new rows to data) and then create final Current column which would have your original values from Current(A) and then missing values replaced with the Smoother columns values
Edit:
I would also suggest out checking out Fit Y by X platform
-Jarmo