Comment about PV

In OpenDocument-v1.2-cd05-part2, 6.12.42 PV, the formula seems to have PV and FV with different signs.  For example,  if Rate == Payment == 0, then:

PV = - FV, or if the Future value is $1000 then Present value is -$1000.  This seems odd to say the least. 

Also the semantics of a payment should be made more clear, that is that a payment is out of the investment.  As in, say I want to put $100 dollars in an investment, then payment would be -100, not 100, so that if I was adding 5 payments:

PV = -(Payment*Nper) = -(-100*5)  = 500 (as opposed to -500). 

Personally I think it would make more sense to invert the sign of payments as well as future value, but that is my preference, and I think I have seen the other way of payments used more often. 



Josh Cogliati