Thanks Ray. I have tried the first suggestion and am waiting to hear back from my client to see if anything appears in the Description.
Yes, the docs are confusing. If they are confusing for you, I can't imagine how they expect someone like me to understand.
One thing I notice is that they give different instructions for each payment type. Am Ex, MC, etc. As you pointed out, Am Ex is different. And in some cases they want you to use L_UPC instead of L_SKU. Honestly, this cart doesn't provide a SKU so it might not matter. But...
I know that the PP Pro allows us to use whatever payment gateway or merchant account we want. Since this is not the case in the Advanced setup (PayPal is used), I wonder if maybe this document is to providing us with what PayPal wants the L_x variables to be. I'm looking around now. In the meantime, I will test your second suggestion of changing just the name and not the indexing once I get feedback on the first test.
Thanks so much for your help!