This work improves a novel Service Selection Method for the development of Service-Oriented Applications in the context of the Service-Oriented Computing (SOC) paradigm. We have defined a Semantic-Structural Scheme to assess Web Services on Interface Compatibility exploring the available information from WSDL documents. The structural information involves data types from return, parameters and exceptions. The semantic information concerns identifiers from parameters and operation names. The lexical database WordNet is used as a semantic basis. Two appraisal values were defined: compatibility gap and adaptability gap. The former is centered on functional aspects. The latter explains the adaptation effort to a successful integration. We validated those appraisals values through different experiments with a data-set of 465 real-life Web Services and measured the results using three metrics from the Information Retrieval field.