A teacher rates up to 5 goals — the ones you wrote, in the school's own words. Every medal adds. There is no rating that takes anything away, and bronze exists so a teacher can be honest about a hard day while your child still earns something.
A day the teacher does not rate is simply invisible. It is never read as a bad day.
If a teacher changes a rating on the same day, your child keeps the higher one. A correction downwards takes nothing back.