We use the 95% rule. Of the average QPS measured at five-minute intervals, the upper-limit QPS is taken by cutting the top 5% monthly. This allows you to limit the billing amount to a certain level even there is a sudden peak, such as when you have suffered a short-term DDoS attack.

Note that QPS for the entire contract means "the QPS value with respect to queries to all the contracted zones and the LB domain name," not "the value obtained by just adding up QPS values tallied up per zone and LB domain name." Therefore, the total QPS value by zone and LB domain name is not necessarily the same as the QPS value for the entire contract.