We observed and grouped common service composition techniques into six patterns with distinct characteristics of their integration intermediary. No pattern is better than others in all business and IT situations. Therefore our analysis suggests a formal methodology in impact and cost analysis to justify the choice of composition patterns in service design. Our contribution leads to an advisory tool consisting of questionnaire, semantic reasoning and assessment map to assist IT architects in making a decision of lasting impact. Through solving the service composition puzzle, we hope further values of service oriented architecture may be demonstrated at a fraction of total ownership cost.