OLAP Pivottable Extensions - Calculated Member Question

I'm using Excel to get at an OLAP Cube and don't have access to the data anyother way. I installed the OLAP PivotTable Extensions and have had success adding calculated members. There are a couple of things I want to do but don't know the proper syntax.

1) I'd like to add a calculated member that shows up in the totals area. An associated assisted with the following code to add a calculated member:

iif(

isempty([Measured].[cost]),

Null,

Avg({time.currentmember.lag(12):time.currentmember},[Measures].[cost])

)

The calculated member shows up for every time frame in the report. I want it to show just one time in the total. Any suggestions?

Thanks,

JCW