I have a series of rows of data, for which I want to write a formula that
calulculates the maximum value of a moving total.
e.g.

period 1 2 3 4 5 6 7 8 9 10 11
sales 1 3 4 6 1 5 6 4 3 8 4

I use a sum offset function to calculate a 3 point moving total of the sales
( the number of points I total is dependant upon another cell entry). This
gives another row of formulas that result in

Rsum 8 13 11 12 12 15 13 15 15 12 4

I then use a simple max function to find the highest value within this row.

Doing it this way means I have to create a corresponding sum offset cell for
every sales cell.

I want to produce one formula that calculates the max of this Rsum for the
row of sales data.

help.