Confusing total changes on instant search hierarchy

We are using the Vue version instant search but have noticed this on the official demos

If you scroll down to “hierarchy” > click “Car Electronics & GPS”, then click “Car & GPS Accessories”, the click “Car Accessories”

You’ll notice that the top level “Car Electronics & GPS” number changes to “6”

Why does it do this cause i’m thinking it should stay at the total which is “1208”, and that is what it does on the level above

Seems odd to me so wonder if someone can shed some light on why it does this.