Bali Top-down Blinds

Bali blinds with the ability to go top-down have no clear UI for how to do that. You get a % meter and two radio buttons, that don’t seem to link to any functionality in particular. Sometimes you move the % meter bar down and the bottom goes down, sometimes the top goes down. It is completely unclear. Can functionality be added to support this?

Bali blinds that are regular and only go bottom-up have % mapped to position, and it works flawlessly.