Finding rolling costs for 13 months

Hi Experts,
I need urgent help on this issue

I have a formula

'Sum(LastPEriods(13, CLosingPeriod([Rolling Date].[Month], [Rolling Date].CurrentMember)), [Measures].[Waste Costs])'

which calculates rolling costs for last 13 months
e.g today current month + last 12 months

,but when i drill down to hierarchy level 8 it shows me few records of year 2006 also,i think this shuld not be case,coz formula should show me records till july 2009 (assuming go back 13 months from current date)

can you please guide me are there any corrrections in this formula or if i m going to level 8 -drill down then it will include costs for 2006 also?
I'm unable to make any firm conclusion on this

Could you explain a little more. What is hierarchy level 8?

here level means ......

Please help me in this

Instead of drilling down, what happens when you just browse directly to level 8?

It looks like the measure could be, mapped to the this dimension in a way that makes the month not count back correctly.

how to traverse to level 8 directly?

earlier I was traversing to the path

Paris-->manufacturing dept-->cc pant line 10-->p10 Adhesives Process-->P10 Elastics System

and checked dates that I found it's including 2006 dates also

Now i traversed to the path

P10 Elastics System directly still I'm seeing the same result

Also I traversed to the path  paris-->manufacturning dept and I checked the dates I found it's calculation last 13 month's data

is the formula wrong?

or in case drill down it will find the records associated to child level also

Like i found the formula has scope till paris-->manufacturning dept  and i observed scope of formula ends if i'm drilling down the data

can you please recheck again this?

Thanks in advance for your help