The thing to recall is that the two organizations are dealing with very different kind of programming in grants and contribution programming.
For an organization like NSERC, much of their funding is going to individual doctoral fellowships, graduate fellowships, etc. NSERC and SSHRC are actually able to realize significant savings from the fact that they get a lot of the administration and the conduct of their contributions for free, because of the willingness of individual university faculties across the country to devote their time, gratis, toward the actual overall peer review process for academic research. It's necessary in a peer-reviewed system to have that. So that is part of it.