Yup, that's the problem with Kodak chemistry. It's designed to be used in specific machines with varying modes of maintainence. You brought up developer starter. So did some others recently, not sure what thread. One long time Kodak user didn't use the starter, others do. A quick look at the MSDS showed it to be a restrainer. I.e., a fresh developer batch plus starter will give more consistent developing than without due to the making of potassium bromide as the films develop.
There's a point of diminishing returns with cost per roll decisions. Four dollars vs. one? Sure. One dollar vs. a quarter? Not so much.
And the claims of each of the several companies still making C-41 chemistry about how many rolls it will process are pretty conservative.