If you reverse engineer the "50-level" of the 14 period rsi, you end up with almost exactly the 27 period ema So to calculate the rsi, you can 'reverse engineer' the 'reverse engineered rsi'. This can be done by taking the distance between the current price and the "50-level ema" you can then normalise this by dividing with the atr or the st dev to end up with a chart that's almost exactly like the rsi line As OB/OS levele, a multiplier of the atr or st dev can be used one application for this is to quickly refer to MTF rsi levels by multiplying th 27 ema value with the timeframe multiplier as it turns out, I discovered that the ema's with multiples of 27 as a period align with the 50-level line of the rsi of all the corresponding timeframes.