Basically that.
If your kid comes home with a report with a wanky flightpath on it, take it with a hefty pinch of salt. There’s no science or data behind it.
If your KS3 kid comes home with a report that says they are currently working at a GCSE grade 4 in Science (or worse a 4+, implying technical accuracy), then know that it is made up, no one knows what a grade 4 in science (or any subject really) looks like, and applying GCSE grades to kids who aren’t studying GCSE courses is just nonsense.