Some wise words. Thanks.

You're correct - we are additive on the nonprofits' existing revenue (other than cases where they would be switching from another service). The problem that I seemed to be encountering in emails from prospective customers (actual nonprofits) was that it was psychological. Nonprofits are pressured to keep their Administrative and Fundraising expenses low. They tend to have a gut reaction when they see a percentage that's above 0%. They also tend to think about how much they could raise. When they think of it in very aspirational terms, the % seemed prohibitive.

Of course, I could be wrong on all of this. I've only been doing it for 2 weeks...