Ed, the table in the DB should be names "customers_whole" and the $_SESSION should be named "customer_whole" without the "s." This is just the difference in naming conventions Zen-Cart likes to keep plural table names so I stick to that for the DB. But in my writing it doesn't help me to stick to a plural $_SESSION name when I'm only referring to one customer. All right enough explanation there, but all in all the module will never work with the table named "customer_whole" change it back to "customers_whole."
Is the price changing according to the customer's login level? I'd check the includes/modules/pages/login/header_php.php file and see if it's uploaded correctly or properly saved. Next I'd log out of Zen Cart make sure your test customer is set to a whole sale level and then log back in and retest. Let me know if this helps.
Cheers,
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