Final answer:
Work package estimates in project management should not include allowances for contingencies, which are addressed at the overall project budget level to avoid double-counting in aggregate project estimates.
Step-by-step explanation:
Work package estimates in project management should include all costs directly attributable to the work package itself. This typically encompasses items such as labor costs, materials, and overhead costs. However, they should not include allowances for contingencies. Contingencies are generally addressed at a higher level, typically within the overall project budget, as they are used to cover unforeseen events or risks that are not specific to any one work package. Including contingencies at the work package level could result in double-counting when aggregating the estimates for the entire project.