It's nice - but I find the BitcoinWisdom mining calculator much better still. Yours only calculates your earnings after the next difficulty increase. In reality, a miner needs to be able to model their returns after each difficulty increase. Without taking that into consideration, a miner will have an over optimistic expectation of return. Also - you should factor in the initial cost of hardware as well. With a couple more updates, I think this would be great!
The profit chart does actually factor in a changing difficulty over time, but the output tables don't. I could see how that would be confusing. I think I'll change the second table to account for changing difficulty. Thanks for a feedback, that's super helpful!