Shell Programming and Scripting

Let me address a few things, not necessarily about optimization, but rather basics of scripting in the shell.

Code:

#!/bin/ksh

missing highlighted.

Try to double quote variable deference. That has some benefits.

Code:

$(cd $SourceLocation; ls)

ls is an interactive tool that most of the times is not necessary for scripting. ls is specially not an appropriated way to feed a for loop, due to the many ways it can break your code.
Separate the cd command from the loop. Do a cd first, verify that you are in the directory you want (in case that the variable does not contain an existing directory, it will cd into your home).
file is already a command, try to avoid it as a variable as a manner of clarity.

Code:

cd "$SourceLocation"
if [ "$PWD" != "$SourceLocation" ]; then
    echo "$PWD is not the directory you want, bailing out"
    exit
fi

for filename in *; do
     ...
     if [ ! -f "$filename" ]; then
         ...
     fi
     ...
done

Could substitute your for loop. However, if the shell can not expand to any files, the for loop will happily pass the string "*" along the way, and your logic will process it.