These levels are based on price around earnings day. I have implemented support for 2 calculation modes:
Mode 1: Level = (low of 1 day prior to earnings + high of 1 day after earnings) / 2.0 Mode 2: Level = (hl2 of 1 day prior to earnings + hl2 of 1 day after earnings + close from earnings day) / 3.0
Chart above shows "Mode 1". Mode can be changed via options page.
This indicator was requested by user @mika2k1ff. I learnt more about this idea from DanV and timwest (Thanks guys :)). BTW, TimWest has an indicators package, "Key Hidden Levels", that has this and more.
Do let me know how you use this, I am very intrigued by the potential this idea shows. Thanks.