AutoZone Inc. on Tuesday reported 5.9% profit growth in the most recent quarter, though results came in solidly below expectations as the replacement-part retailer overhauls its distribution process. Sales at domestic stores open at least a year rose 2% for the Memphis, Tenn., company, which has been working to increase inventory and selection in part by opening mega hub locations and making more frequent deliveries to stores. Chief Executive Bill Rhodes said the company expanded its initiative of increased frequency of distribution center deliveries to 1,600 domestic AutoZone stores and expects by the end of the fiscal year to be servicing about 2,000 of its more than 5,000 domestic stores. The company plans to open four additional mega hubs by the end of the fiscal year. The stock dropped almost 2% in the pre-market session.