Each Currency has two Tariffs a Primary Tariff and an Additional Tariff.
Primary Tariff The Primary Tariff represents the cost of delivering the Currency if it is the only Currency triggered in a patient episode. Where more than one Currency is triggered in a patient episode, the Currency with the most expensive Primary Tariff is selected as the Primary Tariff.
Additional Tariff The Additional Tariff represents the cost of delivering multiple additional Currencies triggered in a patient episode. Where more than one Currency is triggered in a patient episode, all the Currencies apart from the most expensive one are charged at the Additional Tariff rate.
Rational This approach allows the Tariff system to bundle multiple activities into one patient episode and not double account for activities such as 'patient meet and greet' or health promotion which appear in most care pathways. Additional Tariff charges account for all the unique activity delivered in a patient care pathway such as drugs and other consumables but they only account for a proportion of the duplicated work. This allows the Tariff system to offer a marginal cost model of charges.