Where a contract is voluntarily advertised ie where it is not expressly covered by the requirements of the legislation, then the requirements are not binding in relation to the prescribed minimum timescales.
Thus, for reasons of transparency or increased competition, it may be beneficial for a contracting authority to choose to use the European forum even where it is not necessary.
Note, however, that the timescales given to tenderers to submit responses should be sufficient and reflect the complexity of the requirement.