2.1.1016 Part 1 Section 18.17.7.253, PMT

a.   The standard places no restrictions on nper.

In Excel, if nper is 0, then #DIV/0! is returned.

b.   The standard states that the argument type can only be 0 or 1.

Office allows the value for argument type to be omitted or nonzero.

c.   The standard states that the argument type is truncated to an integer.

Office does not truncate the argument type to an integer.

d.   The standard does not specify a default for the optional argument type.

In Office, if the value for type is omitted it defaults to value of 0.