While its nice to base future calculations on past events, bitcoin does not really trend like that. Thats because there are no set hardware release cycles in a year, and no set days where bitcoin will jump in the news and soar in price.

My calc was made to give an average because i was curious. Its easy to put in a few numbers and run an estimate at different difficulty jumps to get an idea of what to expect.

Also, that calculator has so many ads on it, its ridiculous