Newly imported children have different permission to parent

I set up Taxonomy Access Control to deny access to a Tag by default, but to set one Taxonomy parent as allowed.

I also ticked the flag with sets all the Parents dependents (children) to also allow access.

This works great, I have an Area Code (the parent) which shows all its' shops (the children) and everything else is hidden.

The problem is, when I import a new shop for the above Area using Taxonomy Import/Export, the shop is hidden (or denied) by default, even though it's parent is allowed.

What this means is that every time I import a new shop, I need to remove and re-add the permission for the user, which is unacceptable to my customer.

Shouldn't any newly children automatically have the same permissions as the parent?