Fundraising on a contingency basis is not considered ethical. I refer you to the Association of Fundraising Professionals Code of Ethical Standards at afpnet.org. Grant Professional Association’s Ethics Statement echoes their sentiment — see grantprofessionals.org. The funder is awarding dollars based on several variables, including the community need, the efficacy of the project, and the organization’s capacity to implement, deliver, monitor, and sustain the project. The funder is not awarding funds based entirely on the expertise of the (fundraising firm). I urge you to rethink this compensation strategy, and perhaps consider performance-based compensation, such as bonuses, instead.