Copper Company uses the high-low method to analyze mixed costs. The following information relates to the production data for the first six months of the year. Month Cost Hours January $ 4,525 310 February $ 4,835 410 March $ 5,550 560 April $ 4,495 210 May $ 5,715 820 June $ 5,240 510 What is the estimated total cost at an operating level of 920 hours?