Can you explain the 2-3% gap between expected returns and outlays? Seems like a lot more than what is needed for accounting (based on the other main person here posting)

The explanation is simple — nobody can predict exact annual returns, and they tend to fluctuate. We aim to spend at least 5% per year on OSS grants and need to decide if we can spend more on them or should reinvest based on specific annual results. And target earnings should overcome inflation.