51. The secretariat presented informal document WP.29-169-13 regarding cycle beating by software based systems, with TPMS as an example. The expert from EC noted a general concern about test optimisation, not only linked to software-based systems, but instead from the utilisation of certain tolerances or corridors that were provided in testing provisions for conventional product performance checks. He added that, for instance, a type-approval test should be considered valid when a deceleration pulse trace was close to the lower boundary of a corridor, but this should not mean that a re-test would be invalid for conformity of production or for market surveillance checks when a product fails performance requirements if the deceleration pulse trace would be toward the upper boundary of the corridor. Thus, he concluded that the requirements should be met regardless of the tolerances provided (e.g. deceleration, temperature, pressure, speed).