There should be an option in the rebar couplers to change host. For example, if the selected rebar in the screenshot is deleted by mistake, and a new rebar is added in the same place, there should be an option in the couplers to connect it to the newly modelled rebar. In that way, the End Treatment parameter is updated for the newly added bar.
Its bothersome in a big project, to delete the coupler and model them again, since, few parameters have been added to the couplers, which needs to be entered again when a new coupler is added. Takes much time in a bigger project.