From what I've read red-colored plumeria has a lot of variation. (I only have the yellow/white.) The color is seldom red, but more often cerise, carmine, rose and pink. Even these colors can present as grainy, like tiny spots on the petal. I suspect the white flower is a random variation, and the rest of the flowers will be consistently pink-edged with a yellow center. The shape of plumeria flowers can vary also vary quite a bit. See this ARTICLE for more detail.