Stepwise Disc

Key Stepwise Disc in Int Rate Spec refers to an optional boolean that defines how the referenced rate r should be used in a context of discounting a series of cash flows paid at T₁...Tₙ - such as those of a bond -, down to time T, with T being the valuation date, assuming that T ≤ T₁
If omitted, the default is TRUE, which means that each cash flow at Tᵢ, i = 1,...,n should be discounted in consecutive steps, i.e. first discounted down to time Tᵢ₋₁ using the rate r, then the ensuing value further discounted down to time Tᵢ₋₂ using the same rate r and so on until reaching the time T₁ of the first cash flow.
In the end, the so far computed amount is further discounted to the valuation time T.
FALSE means each cash flow at Tᵢ should be discounted in one single step down to the valuation time T using the rate r.