Looks pretty good. I guess customer 2407000 is important.  Also do you use Divisions?  If you do you would need to include the division.

Ha, well they will not be once everyone knows we can script a rush date on every order for their customers.  No divisions.  In an excel formula I was able to leave off weekends and only count business days, is this possible in Sage?  Didn't see any post pertaining to that option.

We had someone who wanted to force users to specifically choose a ship date, instead of accepting a default... so we set the default value of that date field to something impossible (ex. 1999-12-31) and did a pre-write script to block saving an order with that value in that field (...SetError...).

What you're doing should be fine, but an alternate approach might be better as a business process.

To count ## week days, you can use the VBScript "weekday" function for that calculation (...adding a different number, depending on your beginning week day value)... but holidays won't be considered.

Running into same problems with script firing off because of the logic of the import of order data.  I was able to set it to a table-prewrite because we run multiple imports against SO throughout the day so the order eventually gets updated and the UDF set.   So I thought if I could simplify the script to just look at the customerno and then set the UDF with a vbs formula to account for just workdays might be better.  However this script gives an error when entering a SO for this customerno. 

rVal = 0
nCustomerNo = ""

rVal = oBusObj.GetValue("CustomerNo$", nCustomerNo)

If nCustomerNo = "2407000" then

	newDate = DateAdd("w",7,Now())
	rVal = oBusObj.SetValue("UDF_NEEDDATE$", newDate)

End if

Running into same problems with script firing off because of the logic of the import of order data.  I was able to set it to a table-prewrite because we run multiple imports against SO throughout the day so the order eventually gets updated and the UDF set.   So I thought if I could simplify the script to just look at the customerno and then set the UDF with a vbs formula to account for just workdays might be better.  However this script gives an error when entering a SO for this customerno. 

rVal = 0
nCustomerNo = ""

rVal = oBusObj.GetValue("CustomerNo$", nCustomerNo)

If nCustomerNo = "2407000" then

	newDate = DateAdd("w",7,Now())
	rVal = oBusObj.SetValue("UDF_NEEDDATE$", newDate)

End if

You didn't initialize newDate to "", or reformat it... like was properly done in the original post's script.  Both are needed.

It might be easier to just try your original script, but using oSession.SystemDate instead of order date.