Trended Moving Averages

I've always been a firm believer that moving averages probably give a better insight into trends within a business than a simple trend line associated to a set of values such as monthly sales (although I tend to review these two values together). The reason for this is that a trend can be skewed by one or two values that may not be representative of the underlying business such as spikes associated to seasonality or a specific event. When BillD highlighted a query regarding this concept in his comments on Profit & Loss (Part 2) - Compare and Analyse, I thought it would be a great idea to flex our P&L dataset to provide some Moving Average capability.