hey David
,
really thanks for reviewing it. you really pointed out the probabilities which i missed in this formula. 
- when both dates are work dates and present in the same week
- when both dates are work dates and belong to different week.
the last else part in the earlier formula was not considering these conditions. Just updated the formula.
really appreciate for pointing this out to me. very thanks!!!

= If (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM")) =6)
And (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")) =6)
Then (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")+1)-(Floor((DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")))/7)*2)-1)
Else If (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM")) =6)
And (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")) =7)
Then (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")+1)-(Floor((DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")))/7)*2)-2)
Else If (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM"))=7)
And(DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")) =7)
Then (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")+1)-(Floor((DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")))/7)*2)-1)
Else If (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM")) =7)
And(DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")) =6)
Then (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")+1)-(Floor((DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")))/7)*2)-2)
Else If (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM")) =6)
And(DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")) InList(1 ,2 ,3 ,4 ,5))
Then (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")+1)-(Floor((DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")))/7)*2)-2)
Else If (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM")) =7)
And(DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")) InList(1 ,2 ,3 ,4 ,5))
Then (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")+1)-(Floor((DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")))/7)*2)-1)
Else If (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM")) InList(1 ,2 ,3 ,4 ,5))
And(DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")) =7)
Then (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")+1)-(Floor((DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")))/7)*2)-2)
Else If (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM")) InList(1 ,2 ,3 ,4 ,5))
And(DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")) =6)
Then (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")+1)-(Floor((DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")))/7)*2)-1)
Else if (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM"))<7)
and
(Week(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM"))<>Week(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")) )
then (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")+1)-2)
else if (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM"))>7)
and (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM")) InList(1 ,2 ,3 ,4 ,5))
and (DayNumberOfWeek(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM")) InList(1 ,2 ,3 ,4 ,5))
then (DaysBetween (ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM") ,ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM"))+1)
-((Week(ToDate(UserResponse("dpdate" ,"Date2") ,"mm/dd/yyyy h:mm:ss AM/PM"))-Week(ToDate(UserResponse("dpdate" ,"Date1") ,"mm/dd/yyyy h:mm:ss AM/PM")) )*2)
dhirensk (BOB member since 2010-04-04)