I am a teacher, when we make our targets for performance management, we have to target children who we aim to make 3 sublevels now, not 2. SEN children are also included, as we strive to make progress all round in the class, and do you know, sometimes they bloody well do make the targeted progress, sometimes the targeted non SEN children don't and sometimes the SEN don't.
It's not that the teacher or children haven't tried, it's just the targets have to be set and in a perfect world all children would make the desired progress. They don't, never mind the SEN children.