Equity buyback program as a vc round

One of the companies that I am a partner in is raising capital. We are considering offering shares with a repurchase program. We have calculated a CAGR that tracks projected YOY revenue growth and valuation. What is a good way to structure a repurchase program to account for fluctuations in the YOY revenue growth? For example, if our revenue after year 1 post-money is significantly higher and we want to repurchase more shares, therefore returning more of the investors' investment sooner, is there a good way to structure the program to account for this, to give us a discount on the repurchase?