Pro Sites / Pro themes possible Bug

I have pro sites set up with 1 free level and 3 subscription levels, using the theme manager i have set which themes each has access to.

A user with the second level of paid subrcription can see the themes i have enabled for them and those of the next level up (with the warning that they need the final level of subscription to use them)

This is all working as expected but shouldnt they be able to see the subscription level themes below theirs aswell?

They are unable to see them under pro themes or in the normal themes folder.

any ideas?