calculate processing time based on Business Days

[actcognosuser]

Hello Cognos Users,

I am trying to process a transaction based on business days.
If the transaction was made on a weekday after office hours it needs to be processed next day
and if it was received within hours must be processed same day and add 1/2 additional days as processing time
if transactions were made over a weekend/holiday.

Trying to use _day_of_week to check for weekends.Looks like it does not evaluate to a value.

case when ([Transrecdtime]>'07.00.00' and [Transrecdtime]<'18.00.00' )
then ([Transrecdtime])
when ([Transrecdtime]>'07.00.00' and [Transrecdtime]<'18.00.00' and 
(_day_of_week([Transrecdtime],1)=7) )
then(_add_days([Transrecdtime],1))
when (day of the week is sat ...)
when (day of the week is friday.....)
etc...
else(_add_days([Transrecdtime],1))
end