For the reading use case it's important to have the same anchor ids for sections as provided by Core. It would be preferable if Parsoid could do that, and then the Mobile Content Service could just reuse those value, so that the mobile apps use the correct anchor ids for sections.
The more upstream this is the better in sync it is with Core.
See also the email thread starting with https://lists.wikimedia.org/pipermail/mobile-l/2015-October/009886.html. As @Tgr points out the ids need to be unique, too.