WINNIPEG - Canada's third-largest telco, Manitoba Telecom Services Inc, (MTS) reported a 33% drop in second-quarter profit after losing 4,000 residential-phone customers last quarter and additional expenses, including the recent wireless spectrum acquisition. This despite strong gains in its high-speed Internet, wireless and digital TV business.Net income fell to $38 million, from $57 million, a year earlier, whiles second-quarter sales rose 2.6% to $486.4 million, compared with the $484.2 million compared to the previous year. MTS's cell phone subscribers accounted for $71.9-million in the quarter, up six per cent, with the average revenue per subscriber dipping two per cent to $56.46....