I'm trying to wrap up a build. I have a frame, with Dura Ace 10 speed front and rear 10 speed derailleurs (circa 2008). I also have a new pair of Tiagra 4600 10 speed shift/brake levers I plan to use. My brakes are the stock Cervelo brakes that came on all the tri bikes from 2007-2009, nothing special.

My question is, the installation guide says that only the newer SLR shimano brakes with the revised pivot location are compatible with the 4600 series shifters. Is this true? What is the downside of using the like new Cervelo stock brakes I already have? I can't seem to find any consistent info on this.

Thanks for any help!