(78)In order to ensure clients' awareness of all costs and charges to be incurred as well as evaluation of such information and comparison with different financial instruments and investment services, investment firms should provide clients with clear and comprehensible information on all costs and charges in good time before the provision of services. Ex-ante information about the costs related to the financial instrument or ancillary service can be provided based on an assumed investment amount. However, the costs and charges disclosed should represent the costs the client would actually incur based on that assumed investment amount. For example, if an investment firm offers a range of ongoing services with different charges associated with each service, the firm should disclose the costs associated with the service the client subscribed to. For ex-post disclosures, information related to costs and charges should reflect the client's actual investment amount at the time the disclosure is produced.