@pschwede well its a bit morethan that the idea beingthat since the I1 is much smaller than I2 the error will be smaller. I1 represents the maximum advantage a post can have (so in this case some posts still have a 24 hour lead). But if its calculated over a weeks time then that is just 1/7th error rather than an error of 1, so its a fraction of the error. The bigger the ratio between I1 and I2 the less error there is.