2.1.978 Part 1 Section 18.17.7.172, IPMT

a.   The standard states that payment type is truncated to integer.

Office does not truncate payment type to integer.

b.   The standard states that argument type is either 0 or 1.

In Office, any nonzero value of argument type is equivalent to 1.

c.   The standard states that if argument type is not 0 or 1, #NUM! is returned.

In Office argument type is a value of any number.

d.   The standard states that argument per shall be in the range 1-nper.

In Office argument per shall be in the range 1 ≤ per < nper+1.

e.   The standard does not define the error case if argument per is not in the range 1 ≤ per < nper+1.

In Office if argument per is not in the range 1 ≤ per < nper+1, then #NUM! is returned.

f.   The standard does not specify the value of argument type if omitted.

In Office if the argument type is omitted the argument type has a value of 0.