Correct, Kerry. They can be a different as you and your sis. Weird, I know. I posted a thread somewhere one here of a couple of cattleyas that bloomed out for me and they were both the 'same', but ones shape and bloom was quite different though the colors were very similar. Piper's thread on Orchid Naming for Dummies really is helpful. Check it out. The link is in Elena's post.

Cheers,
BD