Companies who build specifically for a customer have unique requirements that are often not understood or dealt with well by some ERP vendors, particularly in the mid-market, who think that systems designed around volume manufacturing fit everywhere.
estimation of manufacturing production costs
in product definition (i.e., estimation, design, and engineering) before anything can be made or bought. In volume manufacturing the product definition work will be amortised over the items' life- possibly thousands of items. Whilst overrun here will effect the time-to-market of the product, it has no effect on the lead-time of any one order, and is therefore not planned in the same way. Moreover, the extensive costs of product definition are absorbed into company overhead or product costing, so an