Generating data used in planning the execution of a manufacturing process includes consistency checks that are performed on proposed groupings of manufacturing operations to make sure that the groupings are defined in a way that enables the information to be aggregated for use in planning. To do this, defined groupings are received for multiple execution-level manufacturing operations that are defined in a manufacturing process execution-level electronic data model and that define a process flow to produce a product. In one aspect, for each of the defined groupings, it is determined whether the defined grouping includes multiple occurrences of a process step definition that has multiple different defined alternative steps, and if so, the defined groupings are changed so that each defined grouping of the defined groupings has no more than a single occurrence of a process step definition that has multiple different defined alternative steps.