It's an accumulative total. The 686 additional census subdivisions, where the information wasn't released for confidentiality reasons, were mostly places where there would be a very small population. That's why there is the confidentiality concern. In terms of census divisions, it is additive: 25% and 15%. However, in terms of the impact on the total 3% of the population for which information was not released, it wouldn't have moved that 3% very much at all because these are very sparsely populated areas.
On May 7th, 2014. See this statement in context.