As i understand it if structural damage is reported or found during a inspection then the SRM which is supplied by the manufacturer is the document that is the authoritive guide to engineers in dealing with that defect ,The SRM will state if the damage is within limits/ out of limits can be repaired/ cannot be repaired/ how it is to repaired ect.
Engineers no doubt use the SRM day in day out and i presume trust it to ensure aircraft remain airworthy, so whats different about this case? why do they suddenly not accept what airbus are saying, ie the damage is acceptable and repair can be defered