I don't have experience with trying to allocate joint costs. This is a highly technical issue, and I doubt that those who are the intended beneficiaries of the new rules understand the issue enough to care about it. Probably someone closer to this issue can do a better job than I of describing what's at stake here. Indeed, part of the point of this post is to try to start a discussion about what these standards are going to mean for scrupulous nonprofits once they take effect. Here is my attempt at providing a fuller briefing about what's going on.
Donors care about it.
Many believe that finding an organization with a low CFR is equivalent to finding an honest, trustworthy organization that really delivers effective services. Watchdog organizations care about it. A fixed ceiling on CFR is included in some published standards. The IRS appears to care about it. Much of the work of preparing a 990 involves sorting things out to complete Part II, and it is the procedures for doing so that are affected most strongly by any changes to these rules.