In my experience Paph. primulinum has solid green foliage. Yours appears to be mottled. As far as I know there is no chamberlianianum var. primulinum (primulinum is considered a species in its own right). Could it be a primary of chamberlianianum x primulinum?
Another flower finally opened on my friend's plant, so here it is. According to Orchidroots, if it is "X" not "V", the grex is Paph Amelia Hart Alexander. I am having trouble finding any pics of the cross