Thank you so much for the note!

Yes, you are right! The max WR calculation is based on the assumption that, by the end of X years, your portfolio will be zero at the end.

I hinted about it, but I should have been more explicit.

In the first year of your retirement, you can safely withdraw the amount of no more than 4% of your stocks + bond portfolio. For each subsequent year for 30 years, you can continue to withdraw the same amount with inflation adjustment, without depleting your portfolio.

So it is important to keep expense under the max WR.