OBJECTIVE 10 Calculate activity- based costs for cost objects. Examine the last two items in Exhibit 5-10. Notice that traditional cost- ing indicated higher costs for the high-volume residential accounts and sub- stantially lower costs for the low-volume commercial accounts. The ABC cost per account for residential accounts is $2.28, which is $1.41 less than the $3.69 cost generated by the traditional costing system. The cost per account for commercial accounts is $14.57, which is $8.42 more than the $6.15 cost from the traditional cost system. Management's belief that traditional costing was undercosting commercial accounts was supported. PPC's management now has the cost information that they think is preferred for planning and decision-making purposes.