Springers are mechanical things that have many moving parts. They have pistons, seals, springs, trigger assemblies (which have many parts of their own) that wear and mate with one another. As all these parts move and wear together over hundreds and thousands of firing cycles, they "mesh" and "mate" with one another and become smoother in their action. It's kinda like a new car. As the engine with all it's new internals gets a few miles on it and becomes "broken in", the fuel economy usually increases. It's because all the bearings, journals, piston rings ,etc have mated with one another and the engine becomes more efficient. A springer gets better with the miles as well. I don't know if this explanation helps, but I hope so.