The batch quantity of a bill of materials is the ideal size of a shop order. That ideal size depends on setup time, de quantity that can be produced per working day (500 piece) or for example the capacity of a machine (1.000 liter in a single run). If the MRP calculation shows a gross requirement of 475 pieces it may be more efficient to produce 500 pieces. If the batch size is 200 liter, and the gross requirement is 450 liter, the advice may be to produce 600 liter (3 batches). We just added (February 2019) functionality ‘to round up to batch quantity’.