Cloud balancing with different optimization algorithms

While using "Cloud Balancing" example with different optimization algorithms the result is always the same for different data sets. 
Is it a default behavior or something else needs to be enabled in addition to changing the optimization algorithm in the "cloudBalancingSolverConfig.xml" file:
i.e.: 
<!-- Power tweaked optimization algorithms configuration -->
<constructionHeuristic>
<constructionHeuristicType>FIRST_FIT</constructionHeuristicType>
</constructionHeuristic>