Indeed there is an algorithm in place to determine which teas show up on the blends page. With over 1000 blends created, we needed a means to highlight only the popular ones. The formula takes into account each blend's sales in addition to it's lifetime.
Rest assured that even if your creation does become delisted from the signature blends page, everyone will still be able to access/purchase it from your own customer profile page.
Hope that clear up any confusion,