Dyes, intermediates & specialty chemicals
Multi-stage synthesis producing intermediates and finished dyestuffs, often with saleable by-products and effluent obligations at every stage.
One reaction produces a main product, a by-product and waste, in proportions that shift with input quality. If cost is allocated on a standard ratio, both the main product and the by-product are mispriced, and nobody can say which stage lost the money.
Multi-level BOMs with by-product and scrap valued explicitly, actual yield captured per batch at each stage, and cost variance reported at the stage where it occurred rather than pooled at the end.