MONTREAL – Despite stable subscriber growth, first quarter profits at Cogeco Inc. dropped by almost 30%.The company blamed the result of a one-time favourable income tax adjustment last year for the decrease in profits this year. Cogeco reported net income of $16 million in the first fiscal quarter of 2011, down from $22.7 million in the same quarter last year. Revenue increased by 4.5% to reach $342.8 million.Cogeco Cable added 70,690 Canadian subscribers and 20,179 customers in Portugal this quarter. The growth in cable, Internet and digital phone subscribers, which the company calls revenue generating units (RGU), was a modest 1.2%...