ODF definition: PPMT Summary: Calculate the payment for a given period on the principal for an investment at a given interest rate and constant payments. Syntax: PPMT( Number Rate ; Integer Period ; Integer nPer ; Number Present [ ; Number Future = 0 [ ; Number Type = 0 ] ] ) Returns: Number Constraints: Rate and Present should be greater than 0. 0<Period <nPer. Semantics: The parameters are Rate: the interest rate Period: the given period that the payment returned is for nPer: the total number of periods Present: the present value Future: optional, the future value specified after nPer periods. The default value is 0. Type: optional, 0 or 1, respectively for payment at the end or at the beginning of a period. The default value is 0. =PPMT(0.0875/12,1,36,5000,8000,3) should be error-> Type: optional, 0 or 1 =PPMT(0.0875/12,1,36,-5000,8000,1) should be error-> Constraints: Rate and Present should be greater than 0. =PPMT(-0.005,1,36,5000,8000,1) should be error-> Constraints: Rate and Present should be greater than 0.
> =PPMT(0.0875/12,1,36,5000,8000,3) should be error-> Type: optional, 0 or 1 > =PPMT(0.0875/12,1,36,-5000,8000,1) should be error-> Constraints: Rate and > Present should be greater than 0. > =PPMT(-0.005,1,36,5000,8000,1) should be error-> Constraints: Rate and > Present should be greater than 0. Each of these formulas work in Office 2013. Maybe the definition is just wrong.
Also in Gnumeric, though it produces slightly different results. Type again should be Logical Type = FALSE(). No idea about the context of Rate and Present. Note that the constraint reads *should* be greater than 0, which is not a normative *shall* in the sense of must. See also http://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part2.html#__RefHeading__1017852_715980110 https://lists.oasis-open.org/archives/office-comment/201607/msg00003.html