Calculation Mgr (Business Rules) in Planning 11.1.2.2/11.1.2.3

We are currently running Hyperion Planning 11.1.2.2 (upgrading to 11.1.2.3 this weekend).  I want to set the starting month for an agg based on the scenario.  If the scenario is plan, agg Mar:Feb.  If the scenario is Forecast, agg &FCTMth:Feb.  I thought use an replacement variable.  I created a replacement variable called StartMonth and assigned a default value of &FCTMth (FCTMth is an Essbase substitution variable and the value is set via EAS).  I then added code in the business rule as shown below; however, the StartMonth variable never gets changed to "Mar" even if the {Scenario} is "Budget".  Anyone