You have to call  on different shifts  but the rules are not so simple to set as we can imagine  . With the callback script rules , you can set as many different rules as you want, applying 1 single script.

The rules

You have to call  2 times during the week before to callback on weekend and have 2,5 days  between each attempt. It means if we call   on Monday morning (shift 1)  , the next call must occur  on Wednesday pm (shift 6)

If we want to iterate:

Create shitfs

First set your shifts . Select the task , properties, Callback

 Insert as many shifts as you need

Create script

And then create your script

 Select the cases where you want a callback by shift

Dim arrCalltoshift 'cases
Select Case [CallHistory.LastCallResult]
        Case 1, 2, 3, 5, 9, 8, 11, 14, 15, 6, 15, 12, 14, 22, 23, 24, 25, 26, 27, 28 
     arrCalltoshift = 1
        case else
      arrCalltoShift = 0
end select

Select the next shift

Create a variable 'weekshift'   where

'weekshift'=0 when there is less than 2 calls during the week , else

'weekshift'=1 when there is 2 consecutive calls during the week

if arrCalltoshift = 1 then

Dim weekshift
Dim CallShiftValid(2) 'where (2) is the mmaximum consecutive attempts number during the week

If ([Contact.CallCount] > 1) and ([CallHistory.LastCallShift]< 11) Then
CallShiftValid(1) = [CallHistory.arrCallShift]([Contact.CallCount] - 1)
CallShiftValid(2) = [CallHistory.arrCallShift]([Contact.CallCount] - 2)
End if


if (CallShiftValid(1) <> "") and (CallShiftValid(2) <> "") then
weekshift=1
else
weekshift=0
End if


If weekshift <> 1 then 'less than 2 calls during the week
If ([CallHistory.LastCallShift]<6) then
[Result.CallBackShift] = [CallHistory.LastCallShift]+ 5
Else
[Result.CallBackShift] = ([CallHistory.LastCallShift]+ 5) - 10
End if

If ([CallHistory.LastCallShift] = 11) then
[Result.CallBackShift] = 4
End If
If ([CallHistory.LastCallShift] = 12) then
[Result.CallBackShift] = 5
End if
End if

if weekshift = 1 then
If ([CallHistory.LastCallShift] = 6) or ([CallHistory.LastCallShift] = 8) then
[Result.CallBackShift] = 11
End If
If ([CallHistory.LastCallShift] = 7) or ([CallHistory.LastCallShift] = 9)then
[Result.CallBackShift] = 12
End If
End if
End if

If you want to run this example ,we have enclosed a package (📥 All_KB_Callback_shift_byscript.tsk) that you can import on your platform .