By Michael Guerin Some simple maths suggests Roydon Muscle can win the feature trot at Addington tonight. That is if trainer-driver Bob Butt’s prediction of what his stable runner is capable of is on the mark. Roydon Muscle is a relative newcomer to Butt’s care who after two disappointing performances at Nelson has been excellent in his subsequent two Addington starts. “We was working so well before Nelson I thought he had to be hard to beat up there but he didn’t race up to it,” explains Butt. “I thought…