I like it but I'm not sure the best way to tweak it for those who will having varying expenditures throughout at least part of the plan.
When I first did it putting in the numbers I just recently used for Firecalc I was startled to see a 1.77% success rate!
On Firecalc if you use the manual spending mode then you put in all of your spending for each year. For illustration, I'll use made up numbers.
Year 1 - $100,000
Year 2 - $110,000
Year 3 -$80,000
Year 4 - $75,000
Year 5 and above - $70,000
So I did that (using my real numbers not the ones above) on the this new one and got a $1.77% success rate.
This is apparently because the program was adding the above spending to the default spending of $40,000 a year.
So I went and zeroed out the default of $40,000 a year and left in the above for the spending. I got a much better success rate (I think it was around 90%).
But then I realized there was another way to do it. This time I put in the default spending the amount that was Year 5 and above (in the example, $70,000), then on the spending changes I put in the difference between those amounts and $70,000:
Year 1 - $30,000
Year 2 - $40,000
Year 3 -$10,000
Year 4 - $5,000
Doing it that way, the success percentage was about 98%.
Obviously that is much higher than 90%. However, I don't know which way is better to use for those who will have higher withdrawals earlier in retirement and want to put in manual spending for earlier years.
There were no instructions I could find.
Also, on the link you could copy and put in my browser told me the link was too long to use.