Is "Position Tree Code" mandatorily to be defined in HCM so as to import the Position into EPBCS?

Summary:

We are integrating the HCM Position with the Job dimension in EPBCS Workforce cube. All our HCM to EPBCS integration works except for Position. There is no Position Tree defined in HCM, its a flat list, and so we have not mentioned the "Position Tree Code" and "Position Tree Version Name" in the integration Options screen. But when we try to import, no positions are extracted. We could not find any specific documentation on defining integration options for Position. Can somebody advice if Position Tree is a pre-requisite to for this integration?

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