List of data sheets and column added

It's hard to explain, but I'll do my best.
1. I have a list of SP where I update data from an Excel file and copy / paste in the data sheet view of my SP list.
2. I have a SP custom view of this list that shows only a handful of available columns.
3. I then added 2 additional columns of data to each entry in this SP list.

Question – To keep my data, I have to regularly copy and paste the Excel data as in step 1. If rows are added / deleted, does the data in the columns in step 3 keep their association to the correct data? And if no, is there a way to do it?