My understanding is that, with the latest TCAS/Mode S fits, it doesn't happen, irrespective of rates of climb/desc. (I welcome being proved wrong on that though)
I would like to see any documentation that lets you come to that conclusion. Even in our Boeings delivered this months we do not have that feature.
Rather the documentation tells us that exchange of altitude target is not an ACAS feature and won't be as RAs could be unable to provide a safe distance to another aircraft in the case of a level bust, therefore high rates are still discouraged. Which is of course represented in our SOPs with a max rate of 1500fpm for the last 1000ft outside RVSM and 1000fpm in the last 1000ft within RVSM airspace.