if you are shooting into/past your bullets transonic zone, I think the custom curves are a must. shooting inside of that - i personally don't think it's necessary.
at one point kestrel said that right in the product description.
also - supposedly the elite and non elite both use applied ballistics calculator. the elite has the custom curves, the non-elite just uses G1/G7.
at one point their product description said the non-elite DID NOT use applied ballistics. but an email from a rep at kestrel shared on this forum stated otherwise. and when us non-elite users turn on our kestrels - they say "Applied Ballistics"