Moving-average envelope — a moving average (maType, default SMA) with
upper/lower bands at ±percent % of the centre line: middle × (1 ± percent/100). Appends ${prefix}Middle / ${prefix}Upper /
${prefix}Lower; warm-up rows undefined. (Bollinger bands scale with
volatility, an envelope by a fixed percent.)
Moving-average envelope — a moving average (
maType, default SMA) with upper/lower bands at ±percent% of the centre line:middle × (1 ± percent/100). Appends${prefix}Middle/${prefix}Upper/${prefix}Lower; warm-up rowsundefined. (Bollinger bands scale with volatility, an envelope by a fixed percent.)