The reason why you want to look at 1 -2 months of data is to only see if the bases/panics were properly respected and how many times they were. Is it 100% of the time or only 75%? This gives you an idea of the probability of future trades like this. You don't look way back in time for support levels because they aren't always reliably respected currently on the chart, only recent bases, that's what luc was getting at in the link you quoted.