Don't know the whole picture, but here's a scenario that could fit:
12 months ago the heads of department at the school sit down together:
Maths and Science: "We're really worried about Jonny Smith, he's struggling in Maths and Science and if he has a bad day in the exams next summer he could end up with a fistful of Ds."
Director of Studies: "OK, how about we try and get a C in Maths in the bag this year on foundation papers so he can focus on the science next year?"
Science: "If I can have him 2 more lessons a week I'd be a lot happier"
Maths: "But his mum thinks he ought to be aiming for a B"
DoS: "Well she's paying the fees :smile:, but I guess there's 3 possibilities: (1) he scrapes/middle grounds a C in June and we tick that box and focus on the science next year; (2) he aces a C in the foundation papers, breaking the UMS cap so we put him up a set and go for an upgrade next summer; (3) he misses a C so we try again in November, and June 2014 if necessary switching to the extra science when we can."
All: "Sounds like a good plan, let's get them to buy in at parents' evening."
... it sounds like they may have fallen down on the last part, otherwise does this look like a good school doing the best for a child?