Pretty much this. With ivorys it's definitely not an obvious thing but with a enchi vs enchi pastel, it's easy to see the difference as the one with pastel is much brighter and has much more yellow. As a hatchling a enchi pastel is almost pure yellow and black, as they are they do tend to brown out on the top but you can still easily see the added yellow on the sides vs a pure enchi. With your combo, the pastel will just brighten up the snake and show more yellow vs white.