Getting item rate from different price list in sales invoice item table

I’m trying to implement letting the user choose different price lists to get rate from for each item in a Sales Invoice. I’ve added a field to the items table and am having some trouble with the custom script, this is what I have so far but its not changing the rate value:

This is the custom field I added in the Sales Invoice Item doctype:

This is the client script:

You may have more than 1 price for the item. Can you


to see what is the result?