So we're not talking about a bronco then....
Leaf spring places can put an arch back into a set of leaves to try and bring them back into spec. Perhaps they can even get a bit more sometimes as well. But eventually they will settle again. Might warrant a discussion with the shop.
Add-a-leaf is a cheap solution, but you might get better performance from a helper spring that shouldn't sacrifice the fillings in your teeth.
Re-arching article:
https://www.hagerty.com/articles-videos ... a-Lost-Art