( discussed below ). Clients have contacts within their companies that CMS employees must utilize . For example , the accounting department must know a client ‘ s billing contact in order to know where to send the bill . Maintenance engineers must know a client ‘ s systems engineering contact to know with whom to speak when a problem arises . CMS ‘ s sales representatives must know a client ‘ s sales contact to determine who is responsible for the buying decisions at a client site . Although only these three contact ― types ‖ are currently used by CMS , it is foreseeable that additional contact types might be useful as the company expands into other parts of the world . Currently , a client has only one billing contact , one systems engineering contact , and one sales contact at any given time . This structure is not expected to change ( that is , more than one billing contact per client as of a particular point in time is not anticipated ); however , it is important to retain all contact information over time . That is , when one contact is replaced by another contact , it is essential to retain information about the original contact . For example , assume an invoice is sent to Contact A , who is later replaced by Contact B . If the invoice is lost , CMS must have an audit trail to show that it was sent to Contact A ( who was the known contact for the client at that time ). Clients can have one or more contracts with CMS to provide a variety of consulting services . For example , a single client might have one contract for maintenance of an existing system and also have another contract ( sometimes called a work order by the sales force ) for the development of a new system . Some clients are billed based upon negotiated contracts , which stipulate a pre-determined amount for charges regardless of the number of hours that employees actually work on the contracts . Such contracts are called ― fixed price ‖ contracts . Other clients are billed based on the total number of hours provided by CMS employees multiplied by a rate per employee type per employee hour . These arrangements are called ― T & M