t = current week t-1 = previous week scheduled receipt = SR (if given) On-hand inventory /Projected available balance (t) = on-hand inventory (t-1) - gross requirement (t) (if on-hand inventory (t-1) > gross requirement (t)) On-hand inventory / projected ending inventory (t) = 0 (if on-hand inventory (t-1) <= gross requirement (t)) Net requirement (t) = 0 (if, on-hand inventory (t-1) >= gross requirement (t)) Net requirement (t) = Gross requirement (t) - [on-hand inventory (t-1) scheduled receipt (t)] (if, on-hand inventory (t-1) SR(t) < gross requirement (t)) Planned receipt (t) = Net requirement (t) [ if only rule = lot for lot, else it changes according to the rule.] Planned receipt (t) = (Integer multiples of Lot size) >= Net requirement(t), if lot size given. Planned order release = Planned receipt (t), but offsetted ahead by lead time (i.e., if Lead time 2 weeks (or any unit of time), planned order release will be offsetted by 2 weeks) Product structure