If you use Send Stored Codes, that sends one line from your list for each unit the buyer orders of that item; if they order item qty=3, they will receive three codes from the code list you pasted for that product.
If you use Send Generated Codes, we POST the order data to your keygen script's URL and simply accept whatever raw text output your script returns, which we then forward as-is to the buyer:
http://www.e-junkie.com/ej/help.keygen.htm
Your keygen script would determine how many codes to output based on that order data including item quantity; if your script only outputs one code regardless of the quantity ordered, that one code is what we'd forward to the buyer. If you'd need a developer to set up a script to accomplish this for you, we can recommend the competent, E-junkie-experienced developers listed in our directory here:
http://www.e-junkie.com/ej/developer-directory.htm
