well IMO,
the extra twin time wont make you stand out in a crowd of angry fATPL holders....but the extra experience gained in doing your CPL in a multi will inevitabley help you in your IR stage.
A few people who I have spoken too told me the IR practical flying is enough in itself and wish they had a few extra hours in a twin to make them feel more at home on test day.
Individually, it depends on your circumstances. Think ahead of the game and consider if doing the CPL in a multi will help you in your IR or not.