I think we are caught in semantics for this discussion because you are talking about "direct costs" (X causes Y), but I'm defending the idea of "indirect costs"

I think we are caught in semantics for this discussion because you are talking about "direct costs" (X causes Y), but I'm defending the idea of "indirect costs" (X doesn't cause Y, but you had it lying around, so you used it). Using your previous knowledge inventory is not a direct cost of resource usage, but you'd not have been able to craft that script if you had not known about the tools.