Within phalaenopsis species, it is all aspects of the lip that are diagnostic, not the petal shape.
Petal shape is generally not a very good tool as there can be a great deal of variation within a single species or hybrid, and growers have selectively bred for broader ones.
Here is Phalaenopsis bellina. One is pretty typical of those available in the wild, while the other is much broader.
Even more extreme is this example of Phal. amabilis. The one on the right is almost indistinguishable from many modern hybrids.