Wall tier changes the cost sharply. A stone wall takes 4 rockets, sheet metal takes 8, and an armored wall takes 15. Use the calculator when the route contains several target types.
Check the exact target
Doors and walls of the same broad tier do not share the same raid cost. Pick the deployed target, not just its material.
Count every layer
A route through two walls costs twice the single-wall figure. Splash damage can change a real raid, so treat the table as a clean single-target baseline.
Compare the farm bill
Rocket count is only half the decision. Compare total sulfur and the components you already have before crafting.