Hi
I would definitely speak to the school about this. I am of the opinion that waiting to see what happens can potentially be detrimental to your child's education. The schools don't always have a full picture of a student. They are clearly predicting that the lower marks are what he will likely achieve rather than his potential to achieve. If he is struggling with work at a higher level, this makes perfect sense but if you think there is another issue such as missed learning opportunities, speak to your school about this and come up with a plan to get extra support where he needs it and then how and when he can move sets. The other reason for speaking to the school is to get a fuller picture from their end of your son and his interactions in class. The more everyone knows the better.