How would I implement this nested aggregation?

[xaelm]

I'm developing an AR dashboard and I'm having trouble figuring out how to implement a days sales outstanding (DSO) metric for the entire company.

I'm successfully using the following expression to calculate DSO at the customer level:

sum(AMOUNT_DUE_LOCAL*Days_Past_Due)/sum(AMOUNT_DUE_LOCAL)

But when trying to use the following expression to calculate it for the entire company (while weighting a customer's total amount due relative to the entire company's amount due), I run into an error:

Sum(
  aggr(
   Sum(AMOUNT_DUE_LOCAL * Days_Past_Due)/Sum(AMOUNT_DUE_LOCAL), CUSTOMER_NUMBER)* Sum(AMOUNT_DUE_LOCAL))

/ Sum(TOTAL AMOUNT_DUE_LOCAL)

I've attached a simple Excel example of the desired functionality to clearly demonstrate what I'm trying to do.

Any thoughts?

[Anil_Babu_Samineni]

Perhaps try this way

sum(TOTAL <Customer> (AMOUNT_DUE_LOCAL*Days_Past_Due))/sum(TOTAL <Customer> AMOUNT_DUE_LOCAL)

[xaelm]

Unfortunately that did not work... 

[Anil_Babu_Samineni]

When you say it doesn't help, Do you mean this is not worked anything or no result or any error?