And you also have to factor in whatever 'Progress' pressure the teacher, department and school may be under.
For example, in A levels, if the machine predicted grade was, say, C, but the student was pratting around and doing no work, or having a really hard time making the leap, I could not give an 'expected grade' lower than the C on any official paperwork. That would start a 'why aren't you teaching well enough for this student to achieve their predicted grade' inquisition. And no one wants the extra workload that entails, those 8th days in the week are on ration, apparently!
So your higher than expected grades could mean your DC is doing really well, their teacher has forgotten which one in the class they are, the teacher/dept/school is under pressure in that subject.
You can work it out by looking at any homework commentary, quiz/test marks and an honest chat with your DC. Then a quick chat with the teacher, who is more likely to qualify the details if you ask nicely and with some info to hand.