=RATE NUM ERROR

mtarler  wrote:  ``I still don't understand how +/- don't matter``

It is not an accounting vs engineering thing.  My father the CPA did not understand it.  He turned to me the mathematician/scientist/engineer to explain it.

(Aside....  The OP did not say what the numbers 0.14 and 9500 mean. But it is easier to speak of them as "cash flows", since that is what the terms "pv" and "fv" refer to.).

I think my first exposure to signed cash flows was with the HP12-C calculator, 40 years ago.  It used an internal formula similar to the one that is documented in the Excel PV help page.

But OMG, it was removed recently by the MSFT idiots who have been "simplifying" help pages to the point of being unhelpful.  Fortunately, I captured (and corrected) an image from the Excel 2010 help page, to wit:

With pmt=0, algebraically the solution for FV becomes:

fv = -pv*(1+rate)^nper

And with pv=-0.14, nper=52 and rate=23.8555007215111% (rounded), we calculate fv=9500 (approximately), not -9500.

But I think the concept of signed cash flows is straight-forward, to wit:  inflows and outflows should have opposite signs.

The choice of signs does not matter (it depends on point of view), as long as they are used consistently for each Excel function.

So as a personal preference, I usually choose signs so that the Excel function result should be positive.

(Caveat....  Not all Excel financial functions permit that flexibility.  Historically, the functions that do not were developed by third parties and contributed to the ATP before they were mainstreamed in Excel 2007.  For example, CUMPRINC allows only positive "pv".)