Pivot Table - Create Calculated Column on Running Total

Hi all,

I have a spreadsheet with data from sales and the number of customers over a period of time.

I am wanting to show a cumulative total of sales and customers over the time period as well as the average sale per customer per day - using the running total fields.

I can get the sales and customers working on a running total but I can't get the sales per customer as a running total.

In the two examples attached, the values of the second row onwards are not correctly dividing the number of running total sales by the running total of customers. I have also tried showing the calculated column as a running total but to no avail.

Is there a way around this?

Thanks,

Scot07