Halifax Test Laboratories does heat testing $($HT$)$ and stress testing $($ST$)$ on materials. Under its current costing system, Halifax aggregates all operating costs of $$1,440,000$ into a single overhead cost pool. Halifax calculates a rate per test$-$hour of $$18(=$$$1,440,00080,000$total test$-$hours$).$ HT uses $50,000$ test$-$hours and ST uses $30,000$ test$-$hours. Gary Celeste, Halifax$$s controller, believes that there is enough variation in test procedures and cost structures to establish separate costing and billing rates. The market for test services is very competitive, and without this information, any miscosting and mispricing could cause Halifax to lose business. Celeste breaks down Halifax$$s costs into four activity cost categories.