Whenever you breed discus their is going to be some variation in shape and size. a few may have slightly better shape than the parents which is how discus have been selectively bred to have the nice round shape we enjoy today. However, if you have 2 poorly shaped discus don't expect any fry to be top grade discus. Really, you could expect most to have around the same standard of shape or worse shape than the parents. Typically, when it comes to commercial breeders they use their very very best discus as either show or breeding stock.