The name change was due to novice growers confusing it with Hoya fraterna, I believe.

Treubiana belongs in the same section and complex as Hoya meliflua, Hoya kerrii, Hoya excavata, and Hoya diversifolia (amblyostemma).

It differs from meliflua in not just flower color, but also flower size (not much bigger, but there is a subtle difference), and leaf length/width. Treubiana's leaves can be substantially longer and wider than those of meliflua (upwards of 12 inches long and 4-6 inches wide).

Well, that explains why my "meliflua" leaves are over 20 cms long..... :D