The paper investigates the practical use of the motion plan quality and of the motion plan robustness measures coupled with a deliberative scheduling approach, for computing safe motions for a multirobot. The use of anytime algorithms allows to evaluate the opportunity of looking for alternative solution paths by generating small variations of robot motions in space and in time. By using the concept of plan robustness, we generate several alternative paths that are evaluated through various Performance Indices and Impact Factors, by some heuristic rules. These indices allow to know how much a variation affects a given plan. Finally, we outline some recent experiments.