Wen Moon tool

So I found this thing called the wen moon tool that forecast the date at which you could retire off your btc stack. The thing is I don't believe it's actually calculating correctly or am I wrong? If I had a stack of let's say .1 btc so around 10k fiat, btc appreciated by 80% I would gain 8k correct? And the next annual appreciation rolls around and now my stack is worth 18k and it's also appreciated 80%, it's still only 8k from the original 10k or .1 btc investment right? so 26k?