The leaf of compactum is similarly like standard philippinense, broader and softer, but smaller in size. While the leaf of roebelinii is narrow, hard and thick.
Attached picture is a comparison between both varieties. I took this picture two months ago. In the picture, the right side two plants which in narrow leaves are var. roebelinii. And the left side two plants are var. compactum, in wider and softer leaves.
In additional, maybe in temperature area, all philippinense varieties can have straight up leaves. But I think we still can separate them from the width and substance of the leaves.
Thanks. Really helpful that you have these side by side photos. From this informationa, it like true roebeliniis may be pretty rare then as I’m not sure I’ve seen many photos of Paph philippinense with long narrow stiff leaves.