A tax advisor supports tax classification, accounting, annual accounts, tax returns and communication with the tax office. For the R&D tax incentive, they are especially relevant for the tax claim, cost preparation and treatment of the determined allowance. A funding consultant, by contrast, supports programme selection, R&D argumentation, technical project description, funding logic and clarification request management. The roles overlap in the R&D tax incentive, but they do not fully replace each other. The technical justification of an R&D project often requires engineering understanding and cannot be derived from accounting alone. The tax implementation must nevertheless fit the tax office process, cost logic and bookkeeping. For companies, the best solution is often coordinated cooperation between both roles. The funding consultant sharpens the technical and programme-related story, while the tax advisor secures the tax treatment. Problems arise when technical R&D eligibility, cost structure and tax claim do not fit together.