Currently, the costAdditionalLastPeriod in the ElectricPowerUsageSummary is a single value of type float. This attribute is designed to allow all costs allocated in the IntervalReading classes to roll up to the total provided in the UsageSummary.billLastPeriod less the costAdditionalLastPeriod.

Representing cost results this way removes the need for any pricing information and model to be necessary to understand the EUI data which only renders a summary of the results of the application of a pricing model.

It is suggested that this component of the UsageSummary class be extended so that additional optional line items supporting this attribute can be provided.

This change is also being proposed in the update to REQ18/WEQ19 PAP10.

Suggest extending the attribute currently:
costAdditionalLastPeriod: Float [0..1]

to add additionally optional set of LineDetail (Model from CIM)

costAdditionalDetailLastPeriod: LineDetail [0..*]