Monte Carlo Planner question

This question really has nothing to do with the new Monte Carlo feature on the Lifetime Planner. That is turned on by selecting this box (at the bottom right of the Plan Results graph):

For the "Monthly Savings Targets" what they based on is that you stated some expenses that you want to pay for in the future. If you click on link for one of them it will take you to the edit dialog that was presented to you when you created it. There are three steps/dialogs, the last one looks like this:

In this you will see that you can choose what account to use and how much you have saved for it already, but also how much you plan on savings per month to be able to pay for it when the time comes. It pre-calculates what it would take if you were putting away enough per month to reach that goal. Whatever you set here is what shows up in the Savings Target column under "Monthly Savings Targets". The Calculated Target is what it calculated to save enough to pay for that expense when it comes.

The information is really just so that you might track your progress on saving for the expense. No matter whether you actually save that or not when it gets to that date it is going to add that expense amount to the total expenses for that year.