The purpose of Bollinger Bands is to provide a relative definition of high and low prices of a market. By definition, prices are high at the upper band and low at the lower band. This definition can aid in rigorous pattern recognition and is useful in comparing price action to the action of indicators to arrive at systematic trading decisions. Adding a Moving Average filter which only allows trades if MA and Price are outside of the BB increases the probability of profitable trades with the sacrifice of a lower trade-frequency.
Inputs for Bollinger Bands -> BB Source -> BB Length -> BB Multiplier -> Moving Average Period -> Moving Average Source -> Strategy Condition Options: -> Exit Trades if Price crosses Basis Line -> Enable Moving Average Filter