Our Assessment audit was in September, and our auditor told us with no ands, ifs, or buts, that we shall pursue 100% on-time delivery. Anything less requires corrective action. On the other hand, our consultants told us to set a reasonable goal such as 98% and try to achieve. The auditor did not buy this so, once again, it all depends on who you talk to at that moment. My advise is shoot for 100% on-time and get corrective action when you miss.