Which analysis abc in part b or traditional in part c gives

Question

Paints-R-Us Company provides painting services to commercial clients. By tracking overhead follows: costs in an activity-based costing system, the company can assign the proper overhead costs to each completed job and client. The 2012 data from its activity-based costing system is as 

The "Other costs" pool consists of organization-sustaining costs.One of Paints-R-Us clients contracted for 10 offices to be painted during 2012. This contract required a total of 90 hours of painting. For this contract, the client was charged $2,000.

a. Compute the activity rates (i.e., cost per unit of activity) for the activity cost pools. Round off all calculations to the nearest whole cent. 

b. Using the activity-based costing system, compute the customer margin for Paints-R-Us. Round off all calculations to the nearest whole cent. 

c. Assume Paints-R-Us decides instead to use a more traditional costing system in which ALL costs are allocated to customers on the basis of painting hours. Compute the customer margin for Paints-R-Us. Round off all calculations to the nearest whole cent. 

d. Which analysis, ABC in part b or traditional in part c, gives a more realistic picture of this clients true profitability? Defend your answer.