New Thinking said:First and foremost, the calculations for an age 70 amount appear to be wrong when you are putting them in FireCalc..I am just eyeballing them, but there is confusion here. The age 70 amount should not be 76% more than the age 62 amount because the 8 years of COLAs will create a much larger benefit at age 70. So if you are going to compare $13,488 at 62, I would not use $23,738 at 70, but assume a number of inflation such as 3% which puts the age 70 amount up to $30,083..You do not do FireCalc in Today's dollars, so you cannot use the un-inflation-adjusted amount at age 70 either. This is the most common mistake made in calculations and the Spitzer paper may also be making this mistake..I have to review his numbers, but he does state a 76% increase between age 62 and 70, so that is probably what he is doing..As did the University of San Diego professor's article which CFB linked to before (and I am sure he will harrass me for bringing it up again)..But a starting point of $30,083 bersus $23,738 at age 70 is a huge difference..Plug these into FireCalc and rerun the numbers.
It looks like this point is incorrect per Dory36 (FIRECalc's author) http://early-retirement.org/forums/index.php?topic=7732.msg138630#msg138630