"An Excel file is a binary file within a binary file. It contains
several interlinked checksums and changing even one byte can cause it
to become corrupted"
I believe I am going to have to 'rewrite' the 'optional changes after creation' section of my program to read in the existing XLS with
and then overwrite the previous XLS with this new 'modified' copy. I'll post my results when I get this rewritten...(I did notice that 'irronius' errors appear more-so when I tried modifying a cell)