Total Units for each Customer

Hey guys!

I have been tasked with tracking the expected income for our Advertising Department. (I work for a newspaper.) The rate I charge an ad depends upon the total number of advertising units a customer purchases during an entire billing period.

Essentially: I need to have a total of column G for when column B matches the current row. I need this in column K. The value of K should be the same when the value of B is the same.

My programing flow chart I sketched out checked to see if any row in column B that is above the current row matched the current row's data. If it did then it would use that row's value for the total number of units. If it did not it would add up the units from G when B matched the current column.

I attached a document that might help.
FYI: When I say units I mean Column Inches.

Sorry if I'm a bit scattered.
My brain is about to explode.
Thanks for any help!
I really appreciate it.

-Boozik