@FlameRetired
Very interesting. I never bothered to read the online help for that function, but I completely agree with you.
Not only are error values not accepted in any form (i.e as part of a worksheet range, as an argument or as an element of an array passed as an argument), it appears that there are further inaccuracies in the statements given there for this function.
Text for example, is allowed as part of a worksheet range or as an element of an array passed as an argument, but not as an argument. So, for example:
=NPV(-0.9,1,{2,"X",3},4)
is fine, which we would expect from:
If an argument is an array or reference, only numbers in that array or reference are counted. Empty cells, logical values, text, or error values in the array or reference are ignored.
but:
=NPV(-0.9,1,2,"X",3,4)
is not, which would appear to contradict:
Arguments that are empty cells, logical values, or text representations of numbers, error values, or text that cannot be translated into numbers are ignored.
I searched briefly but could find no cases of these anomalies having previously been reported. Perhaps someone here will have an explanation. Failing that, I might raise it officially with Microsoft.
Regards