How are the Buyers guide averages calculated. I ask because I think that the formula used is just a straight linear average based on all the previous generations of a product wieghted equally. I think this is misleading and needs to either be re-weighted, have a moving average (say last two/three generations), or expressed as a series. Though I cannot recall the last value for iMacs, I do believe it was close to 180 days (as I remember thinking "its just around the corner" during the Stevenote at MacWorld) but that the average is now 'only' 186 days after the most recent 15-month wait. 6mo <<>> 15mo. This means that the longer term/multi generational products will have the least accurate recommendations, assuming that most recent past performance is a stronger factor than earlier; something that I do believe is true. This determination of average strongly effects the guides "Recommendation" BUY NOW/BUY/NEUTRAL/WAIT etc. YMMV.