In order to cut down on the type of problems you describe, and to satisfy auditor requirements that ODBC be read only, here is how we handle this situation.
1.) Save the excel sheet to the IFS as a .CSV file.
2.) Create a holding file on the i5 with a file layout that matches the .CSV.
3.) Use the CPYFRMIMPF (Copy From Import File) command to pull the file from the IFS to the holding file.
4.) Process the holding file to move the data the file(s) that need it.
You could create a program that will do all of this for you and then give the user an option on a menu to upload the .CSV after they save it to the IFS.
If you want an example of how to do this, let me know and I will post something for you.