Matching summarized/unsummarized tables

I believe I need a summarized table.

I am using a star schema model that is very clean.  I have a Budget table, Customer Table, Invoice Header Table, and Summarized Invoice Detail Table.

The Budget table has Company, Customer, Year, Period, Gross Sales budget dollars, and Gross Margin budget dollars.  There is a key field which is Year/Period/Company/Customer concatenated together.

The Customer table has customer and sales rep.

The Invoice Header table has Invoice Number, Year, Period, Company, Customer, SalesRep and a matching budget key field to the budget table.  It also has a key to the Customer table.

The Summarized Invoice Detail table has by Invoice number, Gross Sales, Gross Margin and a key matching to the Invoice Header table.  

The challenge is that for any given budget record, there may be multiple Invoice Header records each having a summarized invoice detal record. 

My users have asked for a table report that will show by Sales Rep how well Gross Sales(Sales/Budget Sales) and Gross Margin(Margin/Budgeted Margin) are doing compare to budget for a given Year/Period.  Based of that calculation I am to do conditional formatting on the cell.  I know how to do the conditional formatting.  I know how to use slicers.  I believe the answer involves using Summarized and Related functions but I have not found a good example.

Any suggestions?