If others haven't pointed it out already. The 3 percent COLA is less than the CPI inflation over the time period measured.
Therefore the withdrawals do not keep up with inflation and your spending lifestyle would go down over time.
Some statistics show that retirees spend less in inflation adjusted terms in their later retirement years than in their early years. So just maybe a front loaded withdrawal scheme is appropriate for some people.
on the other hand, many people (myself included) never want to be in a position where later in their retirement they have to cut back on their spending. So for these people, regardless of their actual spending pattern as their retirement progresses, the front loaded spending scheme would not sit well with them.
In my opinion (of which you all are entitled*
), The best scheme is to start with the normal 4 percent safe withdrawal rate from a diversified portfolio. If by chance or skill your (inflation adjusted) portfolio grows faster than the (inflation adjusted) withdrawals then you could reset the withdrawals to reflect the larger balance of your stash.