Are You "oven curing" Your Caliper Paint?
I would do it on a gas grill, before sticking it in an oven.
I used duplicolor cast iron paint on my exhaust manifolds, and they still look the same 5 years later, the paint has really held up well.
But its all in the prep, I sandblasted them before painting, and rinsed the residue from blasting off with brake cleaner.