2.1.1054 Part 4 Section 188.8.131.527, RATE
a. The standard does not define a default for the argument type.
Office specifies that the argument type defaults to 0.
b. The standard states that the argument type may only be 0 or 1.
In Office, if the argument type is nonzero the payment is at the beginning of the period.
c. The standard specifies that an iterative technique is used for the implementation of this function.
Office does not use an iterative technique.