ODFF: DISC function

DISC
* noting again that the formula given needs to divide by YEARFRAC 
not multiply
* I've verified that Excel and Calc both seem to use YEARFRAC 
internally to calculate DISC, therefore where there are problems 
in Excel/Calc with YEARFRAC (already noted by David Wheeler), 
they transfer to DISC. In addition of course, when Calc returns a 
value of YEARFRAC different to Excel, DISC will also be different 
(example 1Jan08 to 2Jan08, basis 1).


David