SCOPE issue

hi everyone,

my scenario is like this:

i have in my time dimension an indicator 1 if the date is in the last 12 months

example: today 11.18.13 so 1 from 12.1.13 till today

i've wrote a SCOPE like this

Scope 
    ([DimCalcPeriods].[Calc Id].&[11] 
,[DimTimeAppealClose].[HierarchyTime].[All]
);

END SCOPE

(DimCalcPeriods) is a floting dimension with codes and meaningful description of periods

in our case "Last 12 months according to appeal close"

an average measure get's null value when slicing with this period

only when i'm slicing this measure with that indicator value 1 in time dimension i do get a valid value!!