Cost roll up with role up scope 'Selected Item Categories' for configured item

Summary: When we roll up the item cost for a configured item, due to change in component cost for any of the item in the structure, it is observed that the if the exisiting star item cost was imported and published directly, without rolling it up, subsequent update does not happen using roll up scope 'Selected Item Categories', it requires a published cost scenario which was rolled up to pick up the updated item cost

Did anyone had similar observation, please confirm. Any supporting document will help