We have had success with the Join Domain provisioning step adding to a specific OU. (We are using 9.6 SP1. )
We used a public variable string to set the OU and the notation we used was similar to your Notation 1.
I think Wade is on a critical point. I have had problems in provisioning if I typed in a value. However, the same value, entered into the public variable pool worked like a champ.
Many thanks, with a public variable it works.