code: private static final Duration parseDurationInFractionsOfMinutes(ProjectProperties properties, Number value, TimeUnit targetTimeUnit, int factor)
     {
        Duration result = null;
  
        if (value != null)
        {
           result = Duration.getInstance(value.intValue() / factor, TimeUnit.MINUTES);
           if (targetTimeUnit != result.getUnits())
           {
              result = result.convertUnits(targetTimeUnit, properties);
           }
        }
  
        return (result);
     }
docs: Parse duration represented as an arbitrary fraction of minutes.
  
  @param properties project properties
  @param value duration value
  @param targetTimeUnit required output time units
  @param factor required fraction of a minute
  @return Duration instance