Thought this plate would be a straight bolt-on to the rear rack job - but it comes with an extra u-shaped bracket that seems to mount to the pannier rack mounting screws and goes under the rear rack assembly. I presume its some sort of additional support - either I'm a bit slow or the Givi instructions are not all that clear (probably both)! Is it needed? - the rack feels pretty solid as it is. Got a bit dark so I've given up for the night but any experience gratefully received!