PowerPivot - problems adding multiple calculated fields (measures)

Hi,
I have a PowerPivot table with Dates in the Columns area, SalesPerson in the Rows area, and a measure to calculate Total_Sales in the values area...

	1st April	2nd April	3rd April	Total_Sales
John	5	10	9	24
Sarah	10	15	2	27
Mike	0	6	12	18

I wish to add a second measure that will display the Average_Sales for each person. When I add the measure to the Values area, I get the following result...

	1st April		2nd April		3rd April		Total_Sales	Average_Sales
	Total_Sales	Average_Sales	Total_Sales	Average_Sales	Total_Sales	Average_Sales
John	5	5	10	10	9	9	24	8
Sarah	10	10	15	15	2	2	27	9
Mike	0	0	6	6	12	12	18

Is it possible to only show the Average Sales in the far right hand column, and not show both measures for each individual date? The kind of result I hope to achieve is something like this...

	1st April	2nd April	3rd April	Total_Sales	Average_Sales
John	5	10	9	24	8
Sarah	10	15	2	27	9
Mike	0	6	12	18

Is this possible, bearing in mind that the pivot will increase in size as a new date gets added each day?

Thanks for any help or advice you may be able to offer.
Best wishes,
Gary

Hi Olly,

Apologies for the slight delay in responding. I've been moving to another home and have not had access to a computer.

Your solution works perfectly - thank you very much for your help. I wish you could see the big smile on my face right now!

Best wishes,
Gary