csv files

Hello, I am using a shopping cart application (PDG) that lets me download a data file (.cvs) of all our products and other data. I am supposed to be able to make changes to that file then upload it in the place of the original. That works for me as long as the I make the changes and save in a text application. But when I open (and make changes or not ) in Excel and save it and try to use that to update my shopping cart data it is not successful. It does not work even if I save it as a text.

If I open that Excel file in a text application I can see that there are a lot more commas in the first row that don't appear in the original file.

For example these are the first 4 rows...

Original File

[Options]
;UniqueName,DisplayName,Tag1,Tag2,...,Tag n,,,,,,,,,,,,,,,,,
[Discounts]
;UniqueName,Customer Category Name,min to max=change,min to max=change,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

After file is opened and saved in Excel

[Options],,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
;UniqueName,DisplayName,Tag1,Tag2,...,Tag n,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
[Discounts],,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
;UniqueName,Customer Category Name,min to max=change

When I open these two files in Excel they appear identical.

It seems easier to me to work with a spread sheet rather than a large text file. What am I missing? Any help?