What is the difference between 'Contract of service' and 'Contract for service' under Consumer Protection Act, 1986?

The Supreme Court of India in the case of Indian Merchants Association v. V P Santha observed that a 'contract for service' implies a contract whereby one party undertakes to render services e.g. professional or technical services to or for another in the performance of which he is not subject to detailed direction and control but exercises professional or technical skill and uses his own knowledge and discretion. A 'contract of service' on the other hand implies relationship of master and servant and involves an obligation to obey orders in the work to be performed and as to its mode and manner of performance.