Proofs sometimes trigger changes. Here's a pair of photos comparing details of proof 1 and proof 2 of the first Calamityware plate (flying monkeys) with some of the changes highlighted. These refinements are needed to ensure that details are not lost. As I've gained more experience with reproducing drawings on porcelain, these tweaks are becoming rare. But proofing will always be part of the process to ensure that the design is right.