72Those provisions allow the Commission to examine, from all possible aspects, the character of the State measure in question which may constitute new aid or the amendment of existing aid in order to overcome its doubts as to the compatibility of the measure with the common market in the course of the formal investigation (see Tirrenia, paragraph 45). The Commission is even required to initiate that procedure, pursuant to Article 4(4) of the regulation on State aid procedure, if the initial analysis of the measures in issue has not enabled all the difficulties raised by the assessment of the measure in question to be overcome (see Case T-95/96Gestevisión Telecinco v Commission [1998] ECR II-3407, paragraph 52, Case T-11/95BP Chemicals v Commission [1998] ECR II-3235, paragraph 166, and Case T-73/98Prayon-Rupel v Commission [2001] ECR II-867, paragraph 42).