You can try these 4 changes and test to see if it works for you ...
Edit the file:
/includes/functions/functions_prices.php
and around line 1240 change the code in RED:
Code:
$display_price = zen_get_products_base_price($product_id);
$display_specials_price = zen_get_products_special_price($product_id, false);
switch ($products_query->fields['products_discount_type']) {
Edit the file:
/includes/modules/products_quantity_discounts.php
and around the line 86 change the code in RED:
Code:
$display_price = zen_get_products_base_price($products_id_current);
$display_specials_price = zen_get_products_special_price($products_id_current, false);
$disc_cnt = 1;
Edit the file:
/your_admin_dir/includes/functions/functions_prices.php
and around line 1157 change the code in RED:
Code:
$display_price = zen_get_products_base_price($product_id);
$display_specials_price = zen_get_products_special_price($product_id, false);
switch ($products_query->fields['products_discount_type']) {
Edit the file:
/your_admin_dir/products_price_manager.php
and around line 844 change the in RED:
Code:
$display_priced_by_attributes = zen_get_products_price_is_priced_by_attributes($_GET['products_filter']);
$display_price = zen_get_products_base_price($_GET['products_filter']);
$display_specials_price = zen_get_products_special_price($_GET['products_filter'], false);
// $display_sale_price = zen_get_products_special_price($_GET['products_filter'], false);
Note: Backup your files and check the results of these changes ...