Hi,
The product listing does not load every prices of the product, just the cheapest one for each quantity.
It uses
$currencyClass->getListingPrices($rows,$pageInfo->zone_id,$pageInfo->currency_id,$pageInfo->filter->price_display_type);
The product page uses
$currencyClass->getListingPrices($element,$ids,$currency_id,$main_currency,$zone_id,$discount_before_tax);
Which load every prices accessible for the vendor and if a quantity have several prices it would keep all of them.
So, if you want to display all prices in the product listing. You have to edit the view "product | listing" and call a mixed function between getListingPrices and getPrices in order to load every prices including with prices with the same quantity.
The feature request is already in our TODO list but does not have any planning for the moment.
Regards,