"While the stewards do not accepts all the arguments of the team, they however conclude that as the regulation is written, the map presented does not breach the letter of [the regulations] and therefore decide to take no futher action."
So basically, because the engine map alters the torque demand at the middle of the throttle travel range and not - as the regulations are worded - at the minimum and maximum throttle travel position, the map complies with the wording of the regulations and hence isn't illegal.
Ross: "I'm sure that's not the end of it".