There may not be a need to specify the expense either way as it's happening in 2016.

If this is a "large enough" amount, then include it as a special expenditure since this is guaranteed spending over normal consumption.

If you need to withdraw assets from retirement accounts to cover spending for a given year, then use special withdrawals.

You basically have it right, but you may not require a special withdrawal if the spending can come out of "normal" consumption.

Best,
Brian

Sounds like you have this right. You may decide to take withdrawals up to a certain amount out of tax-sheltered accounts (perhaps to the next tax bracket) and the rest from savings or Roth or alternatives, if you have them, or you could stagger this over two years (2016-17). By experimenting here you may find a benefit increasing your lifetime consumption / standard of living.

Best,
Brian

If you're using this to decide if/when to make the withdrawals, watch the taxable income column in the income tax report. Compare that to thresholds for marginal tax brackets to see if your actions cause you to pay tax at a higher rate.

Alternatively, you may be able to manipulate your income down below the next lower rate, in certain years, while not causing other years to break into a higher bracket.

Money is fungible. Take it from where results in the highest LSPA after you spend it.

If debt isn't anathema to you, consider borrowing if that preserves invested assets at a higher rate of return than the cost of the loan. Debt involves risk and you're essentially investing on margin, but that's an investment philosophy issue.

If debt is an acceptable option, test the benefits by adding a loan to home it affects. That's different than allowed debt because it's a fixed payment and term. In contrast, allowed debt is basically a line of credit.

You could also borrow some and spend some cash out of one or more accounts.