Quote from BigFunky:
The calculation for S2 is PP - Range, range is (Hi - Lo),
S3 is S2 - Range,
S4 is S3 - Range, and so on...
However, as common-sense would suggest, it is because of the trending power of forex that these levels are very rarely reached.
Actually I have R3= R1 + range, so R4 = R2 + range
R1= 2*pivot - low