To create a maintenance plan, you first need to generate a source wo. All subsequent orders triggered by the maintenance plan are an exact copy of that first source WO.

Generally you will create the source work order specifically with the intention of creating a maintenance plan. In that case you do not want to have that original order on the system included in statistics and lists. Check the "Delete source work order" checkbox when you create the maintenance plan and that order will be disabled and serve only as a source.

In other cases, maintenance plans actions are first tested with a real work order (i.e. an initial work order that supports actual field work). That order is then adjusted and becomes the source of a maintenance plan. In these cases you do not want to disable the original work order as it contains work information. In these cases uncheck the "Delete source work order" checkbox.