I think we are all guilty of being too obsessed with numbers. That said I would like to see the manufacturers state ratings with a plus/minus, e.g. 300 +/- 9 fps. Some comapines use a range (which is the same thing as +/-) but I think ranges lead to some confusion. I work as a consultant for the pharmaceutical/biotech field and I deal mainly with validation of analytical methods and instruments. If you buy 200 mg Ibuprofen tablets, you are getting tablets that were formulated to a target of 200mg Ibuprofen +/- some percentage. The +/- comes from the variability of the assay used to test the tablets, usually around 2-3%. With bows I know there is some variability in the chrono, it also should be calibrated on a regular schedule, depends on the quality of the chrono but yearly is probably sufficient, but even the finest chrono is going to have to some variability. look in the manual, there should be a stated accuracy or reproducibility percentage in the specifications section. That means that any given reading could be off by that stated percentage, now add in the varibility of the scale to measure arrow weight, scale that measures draw weight, arrow lenght, bow string, shooter etc. Next time take your set-up and shoot it 6 times through the chrono, calculate the mean, then the standard deviation, then % relative standard deviation (%RSD) which is the standard deviation divided by the mean x 100. This is sometimes expressed as the coefficient of variability or CV. A scientific calculator (the calculator in windows is a scientific calculator) can do this in seconds. Then have someone else shoot six times and compare the numbers, especially the RSD's. You might be surprised how much variability there is for one shooter let alone two. I would be more impressed with a bow that had a low variability over some fantasic speed number, but companies know our love of numbers and speed rules so that is the first number everybody looks for, I know I do. To me, low variability translates to quality components, properly configured and assembled (something you and I should be less concerned about when plunking over $500 down for a bow). Sorry for the ramble but speed numbers are not absolute and as someone said, within 25 fps (under 10%) is probably not too bad.