54. Where the call for tenders for services provides that the evaluation is to be made in 2 stages, the first stage shall consist of a call for tenders for services without prices following which the selection committee shall retain a certain number of suppliers who shall be invited to participate in the second stage. The number of suppliers to be selected for the second stage must be determined in the tender documents and the suppliers invited to submit new tenders for services must be those having obtained the highest scores.