The indicator reflects the size of the bar. The size is calculated by the following formula: "minuend" minus "deduction". "Minuend" and "deduction" can be any of four values (open, high, low or close). The number of bars for which the size is displayed can be l...
from https://tradingrobots.net/size-of-candles-text-indicator-for-metatrader-5/