Not all officers can get to L35, only pilots. Other Officer aircrew trades have different capped maximum levels of attainment, for me it will be L30.
As for talk of L28 for SNCO aircrew (and I'm not saying they don't deserve it), that seems to contradict the concept (as supposedly pushed by the NAO) that SNCO aircrew will be cheaper!? There won't be much of a saving in terms of the difference between L35 and L28...