A bizz doesn't automatically give you a discount. You must sign up for a Storebælt agreement to get discounts. The agreement only applies on the Storebælt Bridge and not other bridges.
If you are registered for automatic license plate payment from Brobizz, you automatically have a Storebælt agreement and therefore always get applicable discounts.
If you have a bizz without Storebælt agreement, or if you use a debit card or cash, you always pay list price.