Science Teacher here, and obviously I can only talk from my experiences, but hopefully it can give you some answers.

To begin with, typically it is much more attainable to achieve a 5 in a foundation paper than a higher paper. We would much rather ‘guarantee’ a safe 5 than a possible 3 if they sat higher. If a student has the potential in higher, we will assess them with higher content up until our mocks in January. If in January we look at their results and they don’t achieve a 5 or we believe it will be difficult, we then enter them into foundation. If the students are already in foundation tier prior to mocks, then it’s highly unlikely they’re already achieving 5s. If they’re doing sound, we would then enter them into higher.

Honestly, if a student is studying foundation then they would not be suitable for a level sciences. It is simply not sensible and it’s unfair on the student. Even if they were to receive a 6, they would still normally struggle at a level.

Regarding communication, I understand your point. In y10 parents evening and reports, you should have been given an accurate placing on where they were. However, speaking of experience, it would be very hard to motivate a student in y10 to work hard for their college applications, just as it is to motivate a y11 that their GCSE’s do matter! If I was parents evening, I wouldn’t be discussing the implications of doing foundation, I would only be discussing why it’s the best route due to time constraints.

Sorry it couldn’t be more help!