WooCommerce attribute variations

I’m setting up a shirt product.

It has three attributes: Cut, Style and Size.

Cut is Male / Female / Youth
Style is Short sleeved / long sleeved / sleeveless
Size is different for each cut – for example, Youth only need S, M, L – Female cut goes from XXS to XXXL – Male cut goes from XS to XXXXL

So, I create my attributes, and I create all possible sizes, and I ask Woo to create a variation from each option. I run this twice to end up with something like 90 variations.

Now I don’t need them all – I can remove a ton of the Youth sizes, for example – I only need S, M, L. I do this and update the product.

Why do the drop downs on my public page still show every size, with Youth is selected?

It does say this variation isn’t available when I select a Youth XS – but it would be considerably neater if it simply didn’t show it at all – after all, there’s no variable entry for it.

Thoughts?