Steve, in my back-testing, I have a setting that selects a random review time instead of keeping it constant. I ran many simulations on many stocks / ETFs and I found that a lot more often than not, using a review period that falls randomly between 2 and 6 weeks actually achieved better results than doing the review constantly at 2 weeks, 4 weeks or 6 weeks. It provided an additional return of something along the lines of 0.25% per year on average with a probability of more than 70% as I recall. It might not be significant, but it goes to say that there is nothing magical about the month review period and that a bit of randomness actually helps.