Plan item service units are measurable elements of the plan item delivery to a client, e.g., physiotherapy visits, computer training skill sessions. Each plan item has a service unit type associated with it that can be used to determine whether a plan item is based upon a particular number of units or the duration of the plan. An authorized user records the recommended number of units which can be defined for the plan item. These units can be modified up to the defined maximum number of units when the service or activity is being delivered to the client. For example, a case worker creates a Return to Work service plan based on a pre-defined Return to Work template for participant James Smith. James Smith is required to attend 6 computer skills training sessions as part of his Return to Work program. Throughout the course of his treatment, the trainer communicates the requirement for James to attend a further 2 sessions. A supervisor modifies the authorized training sessions from 6 to 8 in order to allow an additional 2 training sessions.