Most likely is sideways to down price action over the next year, with a probable test of the all time high should we get a signficant downside swing. The major (lower) bull is very likely to be tested, but this may occur by going sideways for a year or so.
Less likely, we get a strong bear spike selloff to test the bull .
Bulls see this as the first demonstration of signficant selling pressure, as the bears are beginning to not only sell above resistance (limits orders) but selling below support (stop orders). Since the bulls are only willing to buy below and the bears are beginning to sell rallies, the market has transitioned into a trading range (tight range since November).
Support levels below are likely to find buyers and bears taking profits.
I mean that 20 is most likely used on daily chart to calculate average price of the month
It also works for hourly chart on FX - calculating average price for the day (20 hours)
Then it became conventional use
My point is that the period you calculate - it rather have at least some sence to it... I myself use mostly 24 hours, 120 hours (week) - then 66 days (quarter) and 264 days (year) - and so on...