Correct me if I'm wrong, but this seems to be assuming a seed round valuation of $40 million (it's returning $0 unless the exit is > $40m). That's absurd.
Edit: the assumption of 0.01% is also absurd.
A simplified calculator should include reasonable defaults. This is like a mortgage calculator called tldrCanYouAffordAHouse.com that assumes 25% interest rates and doesn't disclose that.