Order-specific hours are entered and evaluated for the purposes of invoicing within the module Service Management which is created sector-specifically and company-specifically. By entering all work- and service-specific data, a large variety of evaluations / reports can be generated which are oriented towards the customer's wishes and which serve to review quality standards. Furthermore, the evaluations / reports can be used for the analysis of already existing contractual arrangements and offer an excellent aid for any contract negotiations which might take place. For the transparency of the invoicing process and for assisting in managing complaints, external users (e.g. customers) can be provided with their own access. Using the example of an airport handling company, the following model was implemented: Our service management software prepares the creation and administration of contracts of various service scopes. Based on the stored basic contract data, service catalogues are defined individually for various airline companies and aeroplane types and then assessed for proper invoicing. Within a matter of seconds, the generated invoices are passed on to Financial Accounting via an interface so that swift and optimised invoicing is ensured.